I picked up a demo copy of Parallels at Macworld Expo. It installs, but it won't install XP. Using the Express Install option, it keeps complaining that there is a corrupt file in the XP installation. Thing is, each time I try the install, it complains about a different file. The disc is OK - I used it to install in Boot Camp, and no other piece of software is complaining about disc problems. So what is the problem?