I'm not a Redhat user, but I've had similar problems under Mandrake 9.1. I think I adjusted some of the sound settings in KDE, disabling some of the channels that the sound server tries to use. I have a funny feeling this isn't the answer though  Are you using Gnome (the default) or KDE?
I did a bit of a Google search and found this from: http://homepage.ntlworld.com/garrykn...nux/hints.html
'The solution: There are three solutions that I know of. The simplest is to open KDE's Control Center and go to the Sound section and, on the General tab in the Sound Server section, change the 'Autosuspend if idle for' time to 1 second. This gives other apps a better chance to grab the sound card. Another possible solution is to turn the aRts daemon off altogether. In Control Center, Sound, Sound Server, on the General tab, deselect the Start aRts soundserver on KDE startup item. You'll be asked if you want to shut down the server now; just answer Yes. The third solution only works with some cards. In KDE Control Center, Sound, Sound Server, on the Sound I/O tab, select Use custom sound device and enter /dev/dsp2. This forces the aRts sound daemon to use your card's second digital signal processor, leaving the first for other applications. Remember to click 'Apply' to make the settings permanent.'
Hope this is better than nothing 
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