Needing help with Heli Npc getting error attempt to perform arithmetic on a nil

[thefuzz1234555]

I will put the entire code in here but the main error atm is
[Heli Npc] lua/entities/npc_apache2/init.lua:146: attempt to perform arithmetic on a nil value   1. unknown - lua/entities/npc_apache2/init.lua:146

Anyone know how to fix this its at line 146

AddCSLuaFile( "cl_init.lua" )
AddCSLuaFile( "shared.lua" )
include('shared.lua')

//make snpc hurt you
//have bounding box move w/ model
//have it make nicenice w/ npc_soldier

ENT.Alerted     = false
ENT.bleeds      = 0
ENT.StartHealth = 650
ENT.PlayerFriendly = 0
ENT.AttackingMelee = false
ENT.State = 0 //1 is moving to enemy, 2 is staying put
ENT.BreathTime = 0
ENT.Enemy = NULL
ENT.BreathTime = 0
ENT.dead = false
ENT.DestAlt = 0
ENT.rocket_toggle = false;

function ENT:Initialize()

   self:SetModel( "models/cihan_helicopter.mdl" )
   self.Entity:PhysicsInit( SOLID_VPHYSICS )      -- Make us work with physics, 
   self.Entity:SetMoveType( MOVETYPE_VPHYSICS )   --after all, gmod is a physics 
   self.Entity:SetSolid( SOLID_VPHYSICS )        -- Toolbox  
   self:CapabilitiesAdd( CAP_MOVE_FLY )

   self:SetHealth(self.StartHealth)
   self.Enemy = NULL
   //self:EmitSound("npc/attack_helicopter/aheli_rotor_loop1.wav",500,95);
   self.LoopSound = CreateSound(self,Sound("npc/attack_helicopter/aheli_rotor_loop1.wav"))
   self.LoopSound:PlayEx(500,100)
   self.DestAlt = self:GetPos().z + 1000
local phys = self.Entity:GetPhysicsObject() 
if (phys:IsValid()) then
phys:Wake()  
phys:EnableGravity(false) 
end 
end

function ENT:OnTakeDamage(dmg)
  if dmg:IsBulletDamage() then return end;

   self:SetHealth(self:Health() - dmg:GetDamage())

   if dmg:GetAttacker():GetClass() != self:GetClass() && math.random(1,7) == 1 then
    self:ResetEnemy()
    self:AddEntityRelationship( dmg:GetAttacker(), 1, 10 )
    self.Enemy = dmg:GetAttacker()
//if math.random(1,8) == 1 then
    //self.myturrent.Enemy = dmg:GetAttacker()
//end
   end
   self.Alerted = true
   if self:Health() <= 0 && !self.dead then //run on death
print("DIED!!!")
self.dead = true;
self:KilledDan()
   end
end

function ENT:Think()
if self.Enemy:IsValid() == false then
self.Enemy = NULL
elseif self.Enemy:Health(health) <= 0 then
self.Enemy = NULL
elseif self.Enemy == self then
self.Enemy = NULL
end

if CurTime() > self.BreathTime then
//self.EmitSound(self,"vehicles/Crane/crane_turn_loop2.wav",420,100)
self.BreathTime = CurTime() + 2
end

//self.myturrent:SetPos(self:GetPos())

//print(self.TakingCover)
if self:Health() > 0 && GetConVarNumber("ai_disabled") == 0 then

//print( "Think start" );
//Get all the npc's and other entities.
local enttable = ents.FindByClass("npc_*")
local monstertable = ents.FindByClass("monster_*")
table.Add(monstertable,enttable)//merge

//sort through each ent.
for _, x in pairs(monstertable) do
if (!ents) then print( "No Entities!" ); return end
if (x:GetClass() != self:GetClass() && x:GetClass() != "npc_grenade_frag" && x:IsNPC()) then
print(x)
print("..is chassis enemy")
if x:GetClass() != "npc_soldier" then
x:AddEntityRelationship( self, 1, 10 )
else
x:AddEntityRelationship( self, 3, 10 )
end
end
end

local friends = ents.FindByClass("npc_soldier")
for _, x in pairs(friends) do
x:AddEntityRelationship( self, 3, 10 )
end

local friends = ents.FindByClass("npc_tank")
for _, x in pairs(friends) do
x:AddEntityRelationship( self, 3, 10 )
end

local friends = ents.FindByClass("npc_tank_turrent")
for _, x in pairs(friends) do
x:AddEntityRelationship( self, 3, 10 )
end

//set fixed angles
local phy = self:GetPhysicsObject()
if phy:IsValid() then
local velocity = phy:GetVelocity()
phy:SetAngles( Angle(20,self:GetAngles().y,0) )
phy:SetVelocity(velocity)
end

self:FindEnemyDan()

//set the turrents location to our own
//self.myturrent:SetAngles(Angle(-(self:GetAngles().p),self.myturrent:GetAngles().y,0))

if self.Enemy != NULL then 
//apply movement
//print("works")

local wantedvector = (self.Enemy:GetPos() - self:GetPos() + Vector(0,0,80))
local wantedangle = (self.Enemy:GetPos() - self:GetPos() + Vector(0,0,80)):Angle()
local currentangle = Angle(20,self:GetAngles().y,0)
local anglediff = self:GetAngleDiff(wantedangle.y,currentangle.y)
local pitchdiff = self:GetAngleDiff(wantedangle.p,currentangle.p)
local heightratio = (self.Enemy:GetPos().z - self:GetPos().z ) / self:GetPos():Distance(self.Enemy:GetPos())

if self:GetPos():Distance(self.Enemy:GetPos()) > 2300 then
//print("moving")
local phy = self:GetPhysicsObject()
if phy:IsValid() then
phy:ApplyForceCenter((wantedvector:Normalize() * 25000))
end
end
if math.abs(anglediff) < 30 && self:GetPos():Distance(self.Enemy:GetPos()) < 2300 then
local shoot_vector = wantedvector
shoot_vector:Normalize()

local bullet = {}
bullet.Num = 2
bullet.Src = self:GetPos() + self:GetForward()*150
bullet.Damage = 3
bullet.Force = 200
bullet.Tracer = 1
bullet.Spread = Vector( 12 / 90, 12 / 90, 0 )
bullet.Dir =  shoot_vector
self:FireBullets( bullet )
self:EmitSound("apache/fire.wav",500,100)

if math.random(0,200) <= 1 then
local shoot_vector = wantedvector
shoot_vector:Normalize()
local rocket = ents.Create("proj_dan_heli_shot")
if self.rocket_toggle == true then
rocket:SetPos(self:LocalToWorld(Vector(150,40,-20)))
self.rocket_toggle = false
else
rocket:SetPos(self:LocalToWorld(Vector(150,-40,-20)))
self.rocket_toggle = true
end
rocket:SetAngles(shoot_vector:Angle())
rocket:Activate()
rocket:Spawn()
local phy = rocket:GetPhysicsObject()
if phy:IsValid() then
phy:ApplyForceCenter((shoot_vector * 7500))
end
end
//FINISH ME
elseif math.abs(anglediff) < 5 && self:GetPos():Distance(self.Enemy:GetPos()) < 4500 then
local shoot_vector = wantedvector
shoot_vector:Normalize()
local rocket = ents.Create("proj_dan_heli_shot")
if self.rocket_toggle == true then
rocket:SetPos(self:LocalToWorld(Vector(150,40,-20)))
self.rocket_toggle = false
else
rocket:SetPos(self:LocalToWorld(Vector(150,-40,-20)))
self.rocket_toggle = true
end
rocket:SetAngles(shoot_vector:Angle())
rocket:Activate()
rocket:Spawn()
local phy = rocket:GetPhysicsObject()
if phy:IsValid() then
phy:ApplyForceCenter((shoot_vector * 7500))
end
end

if anglediff > 5 then
print("turning positive")
local phy = self:GetPhysicsObject()
if phy:IsValid() then
local velocity = phy:GetVelocity()
phy:SetAngles( currentangle + Angle(0,2,0) )
phy:SetVelocity(velocity)
end
elseif anglediff < -5 then
print("turning negative")
local phy = self:GetPhysicsObject()
if phy:IsValid() then
local velocity = phy:GetVelocity()
phy:SetAngles( currentangle + Angle(0,-2,0) )
phy:SetVelocity(velocity)
end
end
end

if self.DestAlt + 100 > self:GetPos().z then
local phy = self:GetPhysicsObject()
if phy:IsValid() then
phy:ApplyForceCenter((Vector(0.15,0,1) * 5000))
end
elseif self.DestAlt + 100 < self:GetPos().z then
local phy = self:GetPhysicsObject()
if phy:IsValid() then
phy:ApplyForceCenter((Vector(0.15,0,-1) * 5000))
end
end
end

end

function ENT:Touch( ent )
if ent:GetClass() == "npc_grenade_rocket" then
self:TakeDamage(200,ent)
return
end
if self.State == 0 then
ent:TakeDamage(100,self)
end
end

function ENT:GetAngleDiff(angle1, angle2)
local result = angle1 - angle2
if result < -180 then
result = result + 360
end

if result > 180 then
result = result - 360
end

return result
end

function ENT:SelectSchedule()

if self.Enemy:IsValid() == false then
self.Enemy = NULL
elseif self.Enemy:Health(health) <= 0 then
self.Enemy = NULL
end

if self:Health() > 0 then
local haslos = self:HasLOS()
local distance = 0
local enemy_pos = 0

if self.Enemy:IsValid() == false then
self.Enemy = NULL
elseif self.Enemy:Health(health) <= 0 then
self.Enemy = NULL
elseif self.Enemy == self then
self.Enemy = NULL
end

if self.Enemy == NULL then//no enemy
//print( "No Enemy!" );
//play idle sounds every now and then
else
//print( "Enemy!" );
//print(self.Enemy)
print(self.Enemy)
print("..is chassis enemy")
enemy_pos = self.Enemy:GetPos()
distance = self:GetPos():Distance(enemy_pos)
//distance = 4000
        if distance > 2300 then// too far away
self.State = 0//move to him
elseif distance < 2300 && distance > 380 then//if in reasonable distance
self.State = 1//stay put
else//if too close 
self.State = 1//stay put
end
end
end
end

function ENT:FindEnemyDan()
local MyNearbyTargets = ents.FindInSphere(self:GetPos(),1500)
//local ClosestDistance = 3000
if (!MyNearbyTargets) then print( "No Targets!" ); return end
for k,v in pairs(MyNearbyTargets) do
    if (v:IsNPC() && v:Disposition(self) == 1) || (v:IsPlayer() && self.PlayerFriendly == 0 && GetConVarNumber("ai_ignoreplayers") == 0) then
    if (v:GetClass() != self:GetClass()) && v != self then
self:ResetEnemy()
    self:AddEntityRelationship( v, 1, 10 )
      self.Enemy = v
//alerted
self.Alerted = true
      return
    end
    end
end
MyNearbyTargets = ents.FindInSphere(self:GetPos(),5000)
if (!MyNearbyTargets) then print( "No Targets!" ); return end
for k,v in pairs(MyNearbyTargets) do
    if (v:IsNPC() && v:Disposition(self) == 1) || (v:IsPlayer() && self.PlayerFriendly == 0 && GetConVarNumber("ai_ignoreplayers") == 0) then
    if (v:GetClass() != self:GetClass()) && v != self then
self:ResetEnemy()
    self:AddEntityRelationship( v, 1, 10 )
      self.Enemy = v
//alerted
self.Alerted = true
      return
    end
    end
end
MyNearbyTargets = ents.FindInSphere(self:GetPos(),10000)
if (!MyNearbyTargets) then print( "No Targets!" ); return end
for k,v in pairs(MyNearbyTargets) do
    if (v:IsNPC() && v:Disposition(self) == 1) || (v:IsPlayer() && self.PlayerFriendly == 0 && GetConVarNumber("ai_ignoreplayers") == 0) then
    if (v:GetClass() != self:GetClass()) && v != self then
self:ResetEnemy()
    self:AddEntityRelationship( v, 1, 10 )
      self.Enemy = v
//alerted
self.Alerted = true
      return
    end
    end
end
//if ClosestDistance == 4000 then
self.Enemy = NULL
//end
end

function ENT:StopHurtSounds()
end

function ENT:KilledDan()

//create ragdoll
local ragdoll = ents.Create( "prop_physics" )
ragdoll:SetModel( "models/apgb/helicopter_brokenpiece_06_body.mdl" )
ragdoll:SetPos( self:GetPos() )
ragdoll:SetAngles( self:GetAngles() )
ragdoll:Spawn()
ragdoll:SetSkin( self:GetSkin() )
ragdoll:SetColor( self:GetColor() )
ragdoll:SetMaterial( self:GetMaterial() )
undo.AddEntity(ragdoll)

local ragdoll = ents.Create( "prop_physics" )
ragdoll:SetModel( "models/apgb/helicopter_brokenpiece_04_cockpit.mdl" )
ragdoll:SetPos( self:LocalToWorld(Vector(100,0,0)))
ragdoll:SetAngles( self:GetAngles() )
ragdoll:Spawn()
ragdoll:SetSkin( self:GetSkin() )
ragdoll:SetColor( self:GetColor() )
ragdoll:SetMaterial( self:GetMaterial() )
undo.AddEntity(ragdoll)

local ragdoll = ents.Create( "prop_physics" )
ragdoll:SetModel( "models/apgb/helicopter_brokenpiece_05_tailfan.mdl" )
ragdoll:SetPos( self:LocalToWorld(Vector(-100,0,0)))
ragdoll:SetAngles( self:GetAngles() )
ragdoll:Spawn()
ragdoll:SetSkin( self:GetSkin() )
ragdoll:SetColor( self:GetColor() )
ragdoll:SetMaterial( self:GetMaterial() )

//my code
undo.AddEntity(ragdoll)
cleanup.ReplaceEntity(self,ragdoll)

//ignight ragdoll if on fire.
if self:IsOnFire() then ragdoll:Ignite( math.Rand( 8, 10 ), 0 ) end

//position bones the same way.
        for i=1,128 do
local bone = ragdoll:GetPhysicsObjectNum( i )
if ValidEntity( bone ) then
local bonepos, boneang = self:GetBonePosition( ragdoll:TranslatePhysBoneToBone( i ) )
bone:SetPos( bonepos )
bone:SetAngles( boneang )
end
end

//kill our turrent
local bar = ents.Create("env_shake")
bar:SetPos(self:GetPos())
bar:SetKeyValue("amplitude","8")
bar:SetKeyValue("radius","4000")
bar:SetKeyValue("duration","0.75")
bar:SetKeyValue("frequency","128")
bar:Fire( "StartShake", 0, 0 )

//kill our turrent
//self.myturrent:KilledDan()
local blargity = EffectData()
blargity:SetStart(self:GetPos())
blargity:SetOrigin(self:GetPos())
blargity:SetScale(500)
    self.LoopSound:Stop()
WorldSound("ambient/explosions/explode_2.wav",self:GetPos(),500,100)
util.Effect("HelicopterMegaBomb",blargity)
util.Effect("ThumperDust",blargity)
self:StopSound("npc/attack_helicopter/aheli_rotor_loop1.wav")
self:Remove()
end

function ENT:ResetEnemy()
local enttable = ents.FindByClass("npc_*")
local monstertable = ents.FindByClass("monster_*")
table.Add(monstertable,enttable)//merge

//sort through each ent.
for _, x in pairs(monstertable) do
//print(x)
if (!ents) then print( "No Entities!" ); return end
if (x:GetClass() != self:GetClass()) then
self:AddEntityRelationship( x, 2, 10 )
end
//print("Relationship Complete")
end
self:AddRelationship("player D_NU 10")
end

function ENT:OnRemove()
self:StopSound("npc/attack_helicopter/aheli_rotor_loop1.wav")
self.LoopSound:Stop()
end

function ENT:HasLOS()
if self.Enemy != NULL then
//local shootpos = self:GetAimVector()*(self:GetPos():Distance(self.Enemy:GetPos())) + self:GetPos()
//local shootpos = self.Enemy:GetPos()
local tracedata = {}

tracedata.start = self:GetPos()
tracedata.endpos = self.Enemy:GetPos()
tracedata.filter = self

local trace = util.TraceLine(tracedata)
if trace.HitWorld == false then
return true
else 
return false
end
end
print ("no enemy!")
return false
end

This is line 146
phy:ApplyForceCenter((wantedvector:Normalize() * 25000))