Works in studio but not in game?

I've been animating enemies for my game recently and I've had a good base with a model I've been using, but there are some serious problems. The enemy works almost perfectly in studio (however if I put two or more, they attack each other which needs to be fixed) but is completely broken in-game. It will still chase players and attack them, but the animations don't work and some actions cause it to break.

The model itself has too many scripts for me to post here. However, the link leads to the model and can be opened up in studio to be dug into. Any suggestions?

http://www.roblox.com/Drooling-Zombie-item?id=187789986

Basic Script~

local zombie = script.Parent

for _, script in pairs(zombie.ModuleScripts:GetChildren()) do
    if not game.ServerStorage:FindFirstChild(script.Name) then
        script:Clone().Parent = game.ServerStorage
    end
end

local AI = require(game.ServerStorage.ROBLOX_ZombieAI).new(zombie)
local DestroyService = require(game.ServerStorage.ROBLOX_DestroyService)


local function clearParts(parent)
    for _, part in pairs(parent:GetChildren()) do
        clearParts(part)
    end
    local delay
    if parent:IsA("Part") then
        delay = math.random(5,10)
    else
        delay = 11
    end
    DestroyService:AddItem(parent, delay)
end

zombie.Humanoid.Died:connect(function()
    AI.Stop()
    math.randomseed(tick())
    clearParts(zombie)
    script.Disabled = true
end)

local lastMoan = os.time()
math.randomseed(os.time())
while true do
    local animationTrack = zombie.Humanoid:LoadAnimation(zombie.Animations.Arms)
    animationTrack:Play()
--  local now = os.time()
--  if now - lastMoan > 5 then  
--      if math.random() > .3 then
--          zombie.Moan:Play()
----            print("playing moan")
--          lastMoan = now
--      end
--  end
    wait(2)
end