icronk, I had a similar error message running realplay on my KDE box. It turned out that in KDE you have to run the application that outputs sound through artsd (the default sound server) explicitly:
> artsdsp realplay
instead of
> realplay

I assume it should work the same with limewire and xmms. Try running
> artsdsp limewire
and
> artsdsp xmms
to be on the safe side.

Hope it helps.