Outlook 2003 wont keep Word 2003 as html editor

I cannot get outlook 2003 to keep its setting that makes word2003 as my html editor for emails. It keeps telling me that the ‘document cannot be registered’ and that possibly word is not registered or is not the same version as OL etc…Im at my wits end soon. What reg keys need to be modified or what? Any help would be greatly appreicated. Thanks