This error is caused by the NIS 2004 Anti-spam COM Add-in.
We do:
Start Outlook in Safe Mode and disable the add-in. Restart Outlook in normal
mode,
the add-in is re-checked. Removing the add-in also does not help.
When we rename the add-in file MsouPlug.dll for Anti-Spam (located in
C:\Program
Files\Common Files\Symantec Shared\Antispam), the error does not reoccur.
