Don't use the one argument form of system, pass it a list of the arguments instead. This will avoid starting a shell to parse things and you won't need to worry about spaces (or quotes, or semicolons, or . . . ) in filenames. C.f. perldoc -f quotemeta if you're bound and determined to get the shell involved.

Of course, you could just use something like grip or any of the other existing utilities listed in freshmeat.net's CD Ripping category rather than re-inventing the wheel.