Ok, so while I was messing around in this mod, I decided to look at the menu and/or cheats menu, but here's the thing... when I try to alter the settings, for example, the "unlimited ammo" cheat, or the "respawning enimies" option, it gives me an error,

like this,
[gmDoom] lua/doom/convars.lua:29: attempt to call field 'CvarSet' (a nil value)
1. unknown - lua/doom/convars.lua:29
2. unknown - lua/includes/modules/concommand.lua:54

And when I exit the GM_Doom menu, nothing happens, no infinite ammo, no respawning enimies...

I have NO idea why this is happening or if its a bug, so if anyone can help me out here, it would be much appreciated.