Was seeing this error when creating a new email message in Outlook 2003:
"Microsoft Word is set to be your e-mail editor. However, Word is unavailable, not installed, or is not the same version as Outlook. The Outlook e-mail editor will be used instead. An OLE registration error occurred. The program is not correctly installed. Run setup again for the program."
Googled and tried various solutions, none worked for me. Had been messing with services, was pretty sure I had turned one off that Outlook needed.
The solution turned out to be starting this service:
"DCOM Server Process Launcher"
Might also need the two COM+ services.
Services are under Administrative Tools, or run services.msc.
Hope this helps you.