To read the logs, such as /var/log/messages, you have to be root. Use command su
in a terminal and then give your root password. Then you can just cat
the log. Maybe also head
are useful. Read the man pages.
The cd question... Mandrake uses supermount to mount the cdrom automatically, provided of course that you have Mandrake running on your machine. If you mean that you want to boot from the installation cd, I can't help you - I have always had to boot from floppy when installing, through 3 versions of MDK.
To let a program automatically start playing an audio cd, I haven't tried. Shouldn't be too difficult - I hope