Boss Script problem

[Myuu]

I recently started learning LUA and I've got some problems with a boss that I'm trying to make.

The code looks like this at the moment

--[[
    Jahim boss fight (test)
]]

local NPC_ID = 100007

function NPC_OnCombat(Unit, Event)
Unit:RegisterEvent("Jahim_Trash", 3500, 0)
Unit:RegisterEvent("Jahim_FireNova", 10000, 0)
Unit:RegisterEvent("Imp_Spawn", 30000, 0)
end

function NPC_OnLeaveCombat(Unit, Event)
    Unit:RemoveEvents()
end

function NPC_OnDeath(Unit, Event)
    Unit:RemoveEvents()
end

function Jahim_Trash(Unit, Event)
Unit:CastSpellOnTarget(11976, Unit:GetMainTank())
end

function Jahim_FireNova(Unit, Event)
Unit:FullCastSpellOnTarget(30941, Unit:GetRandomPlayer(0))
if (Unit:GetRandomPlayer(0) ~= nil) then
Unit:FullCastSpellOnTarget(30941, Unit:GetRandomPlayer(0))
end
end

function Imp_Spawn(NPCID, x, y, z, o, faction, duration)
Unit:SpawnCreature(100008, -1119, 1741, 89, 4, 14, 0)
end

RegisterUnitEvent(NPC_ID, 1, NPC_OnCombat)
RegisterUnitEvent(NPC_ID, 2, NPC_OnLeaveCombat)
RegisterUnitEvent(NPC_ID, 4, NPC_OnDeath)

There are two main problems. First off all the Firenova spell is really buggy. Sometimes it dosen't do anything for the whole fight. Sometimes it uses it once or twice and then never again, and it always uses it double (I get hit twice instantly when I'm only suppost to get hit once). The second problem is that the Imp dosen't spawn.

When I spawn the Imp manually it dosen't do anything but auto-attack.
This is the code for the Imp.

--[[ Imp Script for Jahim Boss fight
]]

local NPC_ID = 100008

function NPC_OnCombat(Unit, Event)
Unit:RegisterEvent("Imp_FireBall", 3000, 0)
end

function NPC_OnDeath(Unit,Event)
Unit:RemoveEvents()
end

function NPC_OnLeaveCombat(Unit, Event)
Unit:Despawn(10, 0)
Unit:RemoveEvents()
end

function Imp_FireBall (Unit, Event)
Unit:CastSpellOnTarget(33793, Unit:GetRandomPlayer(0))
if (Unit:GetRandomPlayer(0) ~= nil) then
Unit:CastSpellOnTarget(33793, Unit:GetRandomPlayer(0))
end

RegisterUnitGossipEvent(NPC_ID, 4, NPC_OnDeath)
RegisterUnitGossipEvent(NPC_ID, 2, NPC_OnLeaveCombat)
RegisterUnitGossipEvent(NPC_ID, 1, NPC_OnCombat)

How can I fix these problems?

[kreegoth]

Well for one part it seems that your function

function Jahim_FireNova(Unit, Event)
Unit:FullCastSpellOnTarget(30941, Unit:GetRandomPlayer(0))
if (Unit:GetRandomPlayer(0) ~= nil) then
Unit:FullCastSpellOnTarget(30941, Unit:GetRandomPlayer(0))
end
end

Is causing the double firenova.

Atm you have it set up to Cast fire nova then check for targets and if it finds a target to cast it again. It really doesnt make any sense to tell it Do this.. and if you find a target do it again. Same effect would be accomplished by just using the fullcastspell. The same applies with your imp_fireball

For your imps script i dont think combat phases are considered Gossip events.
RegisterUnitGossipEvent(NPC_ID, 4, NPC_OnDeath)
RegisterUnitGossipEvent(NPC_ID, 2, NPC_OnLeaveCombat)
RegisterUnitGossipEvent(NPC_ID, 1, NPC_OnCombat)

Is your console throwing up an error when it attempts to spawn the imp? Sorry i dont have a Arc server to run the lua through to see what it does and i havent used arc in a few years so im just going off what i can see in the script.