Ya clean out all Civ products in your registry also look for a key called 'Securom'. It comes in many forms but its all some type of copy protection that might give false reads(directions) to installsheild
try in here: HKEY_LOCAL_MACHINE\SOFTWARE
This link might help. It has links to other problems of the same type even a solution that requires you to simply download all the files from a external or onboard cd-write and paste accordingly.
Install problems