you said you were running red hat 8. i seem to remember them saying in their news section that the version of mplayer that came with a certain red hat release didn't work. i'm trying to think back, and i'm pretty sure that it was mplayer that said that...although i can't find it anymore. they have a lot of news on their site.
why don't you just go and download it? only this time, get the tarball. it's easier to deal with, IMO.