I really dont think that its aRts problem

but I have found a way to solve that problem
In your console you have to kill your aRtsd process. To view your processes just type
that will show your running processes, then you'll have to kill your aRts process, every process have its number, that is shown in the left side of the process, you have to kill the one that looks like this:
Code:
1543? xxxx /opt/kde3/artsd ...
if your #### is 1543? then you'll need to kill the process this way:
then you'll be able to play the audio in your video.
The bad side of doing this is that you only can play one thing at a time, xmms or mplayer or the sounds from KDE or ...
But for immediate results work fine...
sorry about my spelling i'm guatemalan