MAPI error on Outlook form

[Phill]

I have created an Outlook form which users use to request
logins. This form was created in Outlook 98 and has
scripting in it. Now when you try to open this form using
Outlook 2002 you get the error message: "Cannot start
Microsoft Outlook. Internal MAPI error: an invalid
parameter was passwed to a MAPI function. Contact your
administrator."

Another form (also created in Outlook 98) will open fine.

Any suggestions on what might be the cause or how to
troubleshoot the problem?