Did you erver get a solution on this?We have exactly the same problem with TS 6.5SP2, Patch 1649 on Windows 2003SP1...
The system I am talking about is a migrated store from TS6.1 which was running on Win2000SP4. The User has role "Editor" and in th past there hasn't been a problem with this user. The problem is also not specific to a workarea or user.Personally I think the problem is related to Windows-SP1.