I presume you mean Red Hat Enterprise Linux 5. If you are running the KDE UI, you can install kaffeine, which is a k-desktop video player. It works fine for both video and audio media. I also use VLC as a media player as it handles some media types better than kaffeine. If you don't find them on your system, kaffeine can be installed with the YUM package manager from a command line: sudo yum install kaffeine
VLC can be downloaded for installation from www.videolan.org/vlc/ - you will want the RHEL 5 rpm file. Then you can install it with the command line: sudo yum install <filename>
where <filename> is the rpm file name, including the .rpm extension.
I hope this helps.
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