Simple answer--restart, and hold down command and option just before the hard disk loads.

Details http://docs.info.apple.com/article.html?artnum=10182

Most utilities have an option to do this too (MicroMat has a free one http://www.micromat.com/tt_lite/tt_lite.html)

Still, if you can't open the File Exchange Control Panel, there's a bigger problem going on.

Sherlock has an option to search for invisible files--might be worth using to see if that other music program left something else behind.

Cheers