very annoying hang during ripping

About 10% of the time, I get lockups with DVDrip.  The symptoms are that it'll 
rip a track all the way through, but lockup just before grabbing a frame for 
clip'n'zoom.  Dvdrip will be unable to kill the rip process.  The status bar 
will show "Rip - title # <num> Duration: hh:mm, fps xxx.x".  The progress bar 
will be about 80% of the way over. The log will show it having finished 
ripping, for example:
  Sun Oct  7 11:59:41 2007 Rip - title #4: 10% done.
  Sun Oct  7 12:00:26 2007 Rip - title #4: 20% done.
  Sun Oct  7 12:01:15 2007 Rip - title #4: 30% done.
  Sun Oct  7 12:02:05 2007 Rip - title #4: 40% done.
  Sun Oct  7 12:03:00 2007 Rip - title #4: 50% done.
  Sun Oct  7 12:03:57 2007 Rip - title #4: 60% done.
  Sun Oct  7 12:04:56 2007 Rip - title #4: 70% done.
  Sun Oct  7 12:05:59 2007 Rip - title #4: 80% done.
  Sun Oct  7 12:06:18 2007 Executing command: execflow tcprobe -H 25 -i
  /dat/dvdrip/brisco-1/vob/004/ && echo EXECFLOW_OK Sun Oct  7 12:06:19 2007
  Program stream units calculated
  Sun Oct  7 12:06:19 2007 Not enabling PSU core, because this movie has only
  one PSU. Sun Oct  7 12:06:19 2007 Job 'Process title #4' finished
  Sun Oct  7 12:06:19 2007 Job 'Rip - title #4' finished

The only way to continue to 'clip'n'zoom' and 'transcode' is to kill dvdrip 
and restart.

Playback of the vob files will play perfectly.  However, after transcoding, 
audio and video will invariably be out of sync.

If I get a new copy of the DVD, it never helps.  Every single copy I try will 
have exactly the same problem.


I'm using:
lsdvd  version 0.16
libdvdcss version 1.2.9-r1  (gentoo sub-version numbering -- this is the first 
release candidate of 1.2.10, I think)
transcode version 1.0.4
perl version 5.8.8-r2
dvdrip version 0.98.8