Hi. I am using BtS and i find this annoying. Every time i click on the civ4 icon, it says the BtS loading screen, but then pops up:

Wrong disc inserted blah blah.

But its the right disk..

Help plz, i dont want to keep inserting the disc and going through that long
Do you wish to continue? screens (i got vista so you have to wade through 932525872385732 of those) help plox

I believe I've had this happen to me. Sometimes it'll tell you this if you've had a lot of programs running. Try simply restarting your computer with the disc in and see if that helps. When your computer loads up, don't open any other programs- and close down anything that might be using a lot of memory. Then try it.

Also, I found this thread (http://forums.civfanatics.com/showthread.php?t=238608) which the problem's discussed. Aside from resetting your computer, there doesn't appear to be any other solution as of yet.