What is the exact error message that "it" gives you. If you're booting into KDE and you don't have the sound daemon (artsd) going, you may not hear any sound events. I've got one of those on-board chips, and as I recall Alsa (sound drivers used by Mandrake) supports it. I believe Mandrake 9.1 autoloads the proper drivers and auto configures everything. If you want KDE sound events, you may want to go into KDE's control center and enable artsd.
Your CD drive should "supermount" in Mandrake 9.1. Personally, I think supermount is sort of worthless, but lots of people swear by it. When you put your disk in the drive, Mandrake should automatically mount it (just like in Windows) and all you have to do is double-click on the disk icon on your KDE desktop. The contents will open in Konqueror.
Without more specifics, this is all I can tell ya. Mandrake's website has a TON of documentation, though. And users have their own board, and they are pretty cool about answering newbie questions.
www.mandrakeusers.org--Akshun J