Trying to write CGI script with python...

[Jason Mobarak]

Probably going to need more information about how mplayer is not being
accessed correctly.

CGI uses the shell environment to pass web information to a program...
so maybe this is messing up mplayer. You'll need to augment or wrap
your partners program in order to give you more information about
what's failing (e.g. wrap the call to mplayer in a try/except use the
traceback module to format a traceback if your CGI server is swallowing
it).