I had almost the exact same problem a few weeks ago on a VaxStation
3100.  I would start installing, and then I'd get that error at about the
section were the timezones were loading off of base.  
  I extracted the set to tmp on another machine and it looks like it was
packed incorrectly, several of the files would install in /.. and not in
the /mnt during the install phase, so well... If you have low memory it
may be the cause.  
  I repacked base and didn;t have any further problems.