[K12OSN] Getting sound going with videos

[Krsnendu Dasa <krsnendu orcon net nz>]

I have managed to get mplayer installed and it plays the video on the 
terminals for many different formats :)
Unfortunately it doesn't play any sound :{
Any tips how to get this working?

I am currently using k12ltsp 4.2. (I also have k12ltsp 4.4 server but I 
haven't played around with the sound on that one yet.)
I get sound (ESD) with the following programs at present TuxMath, 
TuxPaint, GCompris, XMMS, Flash websites using Firefox.
I have tried Totem also but I have found Mplayer easier to use. I have 
also tried Windows media player under Crossover Office 5. All are the 
same - video but no sound.

I tried installing Realplayer. Unfortunately I installed version 10 and 
I can't figure out how to uninstall it so I can try version 8.