Glad it was something easy to fix. <img src="/ubbthreads/images/graemlins/party.gif" alt="" />
If it is any consolation, a few other people have done the same thing.
With the UK / North American versions, inserting the wrong disk gives a somewhat cryptic error message, but doesn't cause a crash. The UK version labels the disks as 'install-cd' and 'game-cd', rather than just disk 1 and 2.