I'm sorry last night I accidentally dropped my crystal ball last night and it is not working right and I cannot see what hardware you have.........
You might want to visit Dag Wieers site and learn howto use yum and the rpmforge-release package and maybe re-install mplayer as an rpm package (and maybe some extra stuff you may want); http://dag.wieers.com/home-made/apt/FAQ.php#B
In addition you might want to add some codecs for playback:
tar format; http://www.mplayerhq.hu/design7/dload.html
rpm format; ftp://ftp.icm.edu.pl/vol/wojsyl/greysector/yum/all/i386
Try adjusting which video output your using for mplayer, you should have a number of choices and maybe the one your currently using works but is not the best choice.