Can't Open Inventory

[PiRATE_FR3D]

This is the error I get when someone pushes Q to open their inventory:
[ERROR] gamemodes/perp/gamemode/cl_networking.lua:129: attempt to index field 'InventoryPanel' (a nil value)
  1. CloseInventory - gamemodes/perp/gamemode/cl_networking.lua:129

And here's the code:
function GM.OpenInventory ( )

if (GAMEMODE.ShopPanel) then

GAMEMODE.ShopPanel:Remove()

GAMEMODE.ShopPanel = nil

gui.EnableScreenClicker(false)

LocalPlayer():ClearForcedEyeAngles()

return

end

if (GAMEMODE.BankIPanel) then 

GAMEMODE.BankIPanel:Remove()

GAMEMODE.BankIPanel = nil;

gui.EnableScreenClicker(false);

LocalPlayer():ClearForcedEyeAngles()

return

end

if LocalPlayer():GetNWBool("cuffed") then return end

--slaugh7er

if IsValid(GAMEMODE.InventoryPanel) then

GAMEMODE.InventoryPanel:Remove()

GAMEMODE.InventoryPanel = vgui.Create("perp2_inventory")

RunConsoleCommand( "SLAUGH7ER_InvResync" )

end

--slaugh7er

GAMEMODE.InventoryPanel:SetVisible(true)

GAMEMODE.InventoryPanel:UpdateIcons()

GAMEMODE.InventoryPanel:InvalidateLayout(true)

gui.EnableScreenClicker(true)

end

function GM.CloseInventory ( )

if (GAMEMODE.ShopPanel) then

GAMEMODE.ShopPanel:Remove()

GAMEMODE.ShopPanel = nil

gui.EnableScreenClicker(false)

LocalPlayer():ClearForcedEyeAngles()

return

end

GAMEMODE.InventoryPanel:SetVisible(true)

GAMEMODE.InventoryPanel.HoveredItem = nil -- Remove this variable so it doesn't show the info for the last item the user hovered over next time we open.

gui.EnableScreenClicker(true)
end
I'm just trying to figure out why its not working. If someone can point me in the right direction it would be much appreciated. Thanks in advance.