The problems your getting with the sound are similar to the problems you get with use a webcam and audio at the same time.
Webcam pic ok, but sound interrupted.
It all Depends on the machine spec.
I run the WINUAE on my pentium II with 64meg ram
The games themselves run ok, but the sound is loopy, interrupted
and damn annoying to listen to.
I have yet to find a way of solving this problem.
I try switching to the soundcard installed, no difference.
However, using the same WINUAE on my sisters machine, which is a TOTR
spec, has no problems.
My advice, Upgrade to a top spec machine, or look around for an amiga.
I wish i had never sold mine.
If you manage to solve the problem of the jumpy sound, i would appreciate it if you could let me know how you did it.