[SDPhantom]

It that all the code or do you have an XML file with the frame in it?

In all honesty, for a simple addon like this, you could just hook LootFrame itself.

local ItemList={
    [774]   =true,--    Malachite
    [818]   =true,--    Tigerseye
    [1210]  =true,--    Shadowgem
--  etc...
};
 
LootFrame:HookScript("OnEvent",function(self,event,...)
    if event=="LOOT_OPENED" then
        for i=1,GetNumLootItems() do
            local id=tonumber((GetLootSlotLink(i) or ""):match("|Hitem:(%d+)")) or 0;
            if ItemList[id] then LootSlot(i); end
        end
    end
end);

Note: Line 12 uses a casting method to insure id is given a number to index the lookup table. This is given the inherent behavior of X or Y in which if X evaluates to a false condition (false or nil), Y is used.



PS: From the code example, it appears to be mixed with code from vanilla WoW. Globals like this are no longer in use.