Copy cdemu to /usr/local/bin and make shure you have permission to execute it, copy the .cdemu directory to your home directory. To start, put the line
cdemu --start
in your .xinitrc file.
NOTE: On bsd systems there is no file /proc/interrupts. I use this to make the panel light blink if there is harddisk activity. So this will not work on bsd systems (and maybe some other systems) for now.