Ok, lets make sure you got it typed in right:
"C:\Program Files\Stardock\TotalGaming\GalCiv2\GalCiv2.exe"
vs
"C:\Program Files\Stardock\TotalGaming\GalCiv2\GalCiv2.exe" cheat
Note the space between the " and the word cheat.
If you have it typed in like that...and it's to Galciv2.exe and not GC2Launch.exe, then perhaps are you running Vista? I think I've heard of issue under Vista.