Attempt to call a table value

[Nicksf13]

Hello, I'm recieving this erros:
Attempt to call a table value
FireBullets - [c]: -1
FireGun - wep_default/init:102
Unknown - df_plane/init:141

Here's the code
df_plane/init.lua

function ENT:Think()

	local p = self:GetPhysicsObject()
	if IsValid(self:GetDriver()) and self:GetDriver():Alive() and self:GetDriver():Team() != TEAM_SPECTATOR then
		if self:GetDriver():IsFrozen() || !GAMEMODE:InRound() then
			p:EnableMotion(false) 
		else
			p:EnableMotion(true)
			p:Wake()
			//Throttle controls
			if self.in_speed then
				self:SetThrottle(math.Approach(self:GetThrottle(), self.MAX_SPEED, self.THROTTLE_SPEED))
			elseif self.in_duck then
				self:SetThrottle(math.Approach(self:GetThrottle(), self.MIN_SPEED, self.THROTTLE_SPEED))
			end
			if self:GetThrottle() > self.MAX_SPEED then self:SetThrottle(self:GetThrottle() - 2) end
			
			//Primary weapon
			if self.in_attack then
				if IsValid(self:GetWeapon()) then
					self:GetWeapon():FireGun()
				end
			end
			
			//Primary weapon
			if self.in_attack2 then
				if IsValid(self:GetDriver():GetCurrentWeapon()) then
					//if self:GetHasFuelPod() then self:GetDriver():ShowTip("NoWepGotFuel") return end
					self:GetDriver():GetCurrentWeapon():FireGun()
				end
			end
			
			local vel = self:WorldToLocal(self:GetVelocity()+self:GetPos())
			self.Engine_Sound:ChangePitch(math.Clamp((self:GetThrottle() * 0.18) + (vel.x / 175)^3,20,250),0)
			if self:GetThrottle() == 0 then
				self:SetPlaybackRate(0)
			else
				self:SetPlaybackRate(self:GetThrottle() / self.MAX_SPEED * 0.5)
			end
			if self:GetLastDamage() + 20 < CurTime() and self:GetDamage() > 0 then
				self:SetDamage(self:GetDamage() - 2)
			end
			
			if self:GetDriver():KeyDown(IN_FORWARD) then
				if self.first_time_boost then
					if self:GetBoost() < 50 then
						self.boost_enabled = false
					else
						self:GetDriver():Boost(1)
					end
					self.first_time_boost = false
				end
				if self:GetBoost() > 0 and self.boost_enabled then
					local discharge_rate = -3
					if self:GetLanded() then discharge_rate = -1 end
					self:AddBoost(discharge_rate)
					self:SetThrottle(self.MAX_SPEED * 1.5)
				else
					self:SetThrottle(self.MAX_SPEED * 1)
				end
			else
				self.first_time_boost = true
				self.boost_enabled = true
				if self:GetThrottle() > self.MAX_SPEED then
					self:SetThrottle(self.MAX_SPEED)
				end
				local charge_rate = 4
				if self:GetBoost() < 25 then
					charge_rate = 1
				elseif self:GetBoost() < 50 then
					charge_rate = 2
				elseif self:GetBoost() < 75 then
					charge_rate = 3
					if self:GetBoost() >= 50 and self:GetBoost() <= 53 then
						self:GetDriver():SendLua([[surface.PlaySound("/df/ready_beep.wav")]])
					end
				else
				end
				self:SetBoost(math.Approach(self:GetBoost(), 100, charge_rate))
			end
		end
	else
		self:Remove();
	end
	self:NextThink(CurTime() + 0.1)
	return true
end

wep_default/init.lua

function ENT:FireGun()
	if self:GetPlane():GetAmmo() > 1 && self:GetNextFire() < CurTime() then
		local dir = self:GetAngles():Forward()
		//if self.last_auto_aim_refresh + 0.05 < CurTime() then
			self.auto_target = nil
			local box_size = 0.1
			local range = 4096
			local min = self:GetPlane():GetPos() + (self:GetPlane():GetUp() * -box_size) + (self:GetPlane():GetRight() * -box_size)
			local max = self:GetPlane():GetPos() + (self:GetPlane():GetUp() * box_size) + (self:GetPlane():GetRight() * box_size) + (self:GetPlane():GetForward() * range)
			local ents_in_box = ents.FindInBox(min,max)
			local dist = range
			for k,v in pairs(ents_in_box) do
				if v:GetClass() == "df_plane" and v != self:GetPlane() and v:GetTeam() != self:GetPlane():GetTeam() then
					local distance = v:GetPos():Distance(self:GetPlane():GetPos())
					if distance < dist then
						self.auto_target = v
						dist = distance
						//self:GetPlane():GetDriver():ChatPrint("Targetting player: ".. v:GetDriver():Nick().." "..math.random(1,10))
					end
				end
			end
			self.last_auto_aim_refresh = CurTime()
		//end
		if IsValid(self.auto_target) then
			dir = ((self.auto_target:GetPos() + VectorRand() * 5) - self:GetPos()):GetNormal()
			dir = (dir + self:GetAngles():Forward()) / 2
			///print(dir)
		end
		local bot = self:GetPlane():GetDriver():IsBot()
		local bullet = {}
		bullet.Num = 2
		bullet.Src = self:GetPos() + (self:GetForward() * 10)
		bullet.Dir = dir
		bullet.Tracer = 3
		if bot then
			bullet.Spread = Vector(self.bot_spread,self.bot_spread,self.bot_spread)
		else
			bullet.Spread = Vector(self.spread,self.spread,self.spread)
		end
		bullet.Force = 2
		bullet.Damage = 4
		bullet.Callback = OnPlaneBulletHit;
		
		self:FireBullets(bullet)
		
		bullet.Src = self.gun2:GetPos() + (self.gun2:GetForward() * 10)
		bullet.Dir = dir
		
		self.gun2:FireBullets(bullet)
				
		//if math.random(1,3) == 1 then
			local effectdata = EffectData()
			effectdata:SetEntity(self)
			effectdata:SetScale(self.gun2:EntIndex())
	        util.Effect( "gun_muzzle_flash", effectdata )
		//end
		
		self:EmitSound("npc/turret_floor/shoot"..math.random(1,3)..".wav", 70,100)
		self:SetNextFire(CurTime() + 0.05)
	end
end