Civ3 v1.16f Fixed exe

[Poison Rain]

Hi All!
Could anyone tell me what the fixed exe on
GCW for Civ3 1.16f does? I've cloneCD'd
my original and then updated the exe and
it still requires me to insert the original CD.
Anyone help?

Thanks.
PS. CDRW is Teac - CD-W516EB