I was in the same predicament with the SCJP LearnKey CD--what ended up working for me (using Darwine on a Mac using 10.4) was copying all the files from the CD to a folder on the desktop. Running LaunchTraining.exe from the folder seems to work then (though I've only just started working through the quiz questions, so I can't say for sure if ALL features on the CD work). Another thing to note is that the CD is still in the drive--I haven't tried it with the CD ejected yet. Hope this helps!