ToastMount 2.0 and later requires Roxio Toast 6 and Mac OS X 10.3 (Pather).
ToastMount uses an internal component of Toast to provide its functionality.

ToastMount does not support anything that Toast does not, but you will not need to start up Toast and select some menus, instead you can simply double-click on a CD image file.

If you still use Toast 5 or Mac OS X 10.2 (Jaguar), check out ToastMount 1.2.1 or try ToastMount 2.0 and tell me if it works for you. I can't test Toast 5 because I do not have it anymore...