I just went through this the other day and someone else may be wondering why - and some of the programs won't let you know that they can't open certain device files (but running "strace program" will). If you are running Mandrake v7.2 and kmp3 dies with a segmentation fault or kscd won't work nor kmix won't work and may be you recently upgraded your kernel then check file permissions for the devices that the following links point to /dev/cdrom, /dev/mixer, /dev/dsp. Modifying these devices to be other readable and writable got these programs working for me again.
