A/V sync issues in cluster mode

I've built up a fancy cluster with 24 cpu cores to process large DVD
collections.  I'm starting to get frustrated with the results.  If I
process the entire movie on a single node, the resulting video looks
and sounds great.  If I process it with the cluster, the audio gets
out of sync with the video.  I see directories left over in avi/001,
like audio-psu-00 and chunks-psu-00.  It seems like bits were left
during the merging process and the result is A/V sync issues.

I'm using Ubuntu 8.10 w/ 0.98.6-0.0ubuntu2 on most of the computers,
but one system is running CentOS5 with 0.98.7.  Is the version
mismatch between the nodes causing me problems? Or are A/V sync issues
common in cluster mode?  I could just run all these systems as single
DVD ripping stations, but I think I'd get much better utilization if I
could run the jobs in parallel across the cluster.

--Ron