Body Blank Using MAPI and Outlook 2003

[OrWolf]

I have a third-party application that make a MAPI call to create a new message with the From, Subject, and Body fields. In Outlook 2000 and in some 2003 clients this works fine. On the working workstations using Outlook 2003 the message says Plain Text. On mine the message is not getting created as HTML. Both Outlook clients are configured to use HTML by default. Any ideas?