If your still having problems with the audio object, this might help ?
<img src="http://dl.dropbox.com/u/15858089/X2audio%20solution.png">
I use this method on my beatbox project.
The first line activates the red line which moves fron left to right.
When it collides a blue object, a sound is played.
I only use one X2Auduio object (global)
Hope it helps
regards
chrisbrobs