Thanks for all the help,
Paul hit the nail on the head. Mplayer likes an interactive shell. Changing
the redirection of output streams helped me fix the problem:
Here is my new crontab that works:
0 22 * * 1-5 /home/xxxxxx/scripts/radio2 >> /dev/null 2>&1
5 2 * * 1-5 killall -9 mplayer >> /dev/null 2>&1
Thanks for the help everyone,
Kevin