I'm having a persistant problem with this and cannot get Entourage to open. Here's what I've done so far, with no change in results:
  1. retrieved a copy of the database from Time machine from the day before I first experienced the problem.
  2. Repaired permissions about a dozen times (using OSX 10.6). Though, there are a number of recurring items.
  3. Compacted the database.
  4. Rebuilt the database.

Does anyone have any other suggestions?