Yes, you've got it there, to a tee!
Uninstalling MMJB caused the problem
(thanx for finally confirming this)
It deletes the AudioCD regkey when you uninstall it,
further proving how craply programmed it is.
The only way to fix the problem is to recreate this regkey.
I don't use WinXP and only knew the reg fix for Win9x/ME . . .
Thanks to Atmo for providing the info so I could create the reg fix.
As for Nullsoft including the regfix in the program, well yes, it would be nice... but only if they gave me credit for it