trouble publishing to organizational forms library
 

I have created some staff leave application forms for my company and
published them to the organizational forms library. They seem to work for
most people but a few get an error message when trying to open them: "The
form you selected cannot be displayed. The form required to view this
message cannot be displayed. Contact your system administrator."

We are running exchange server 2003 with some staff using outlook 2007 and
others using outlook 2003. So far the problem only seems to appear for users
with outlook 2003 (although some 2003 users can access them with no
problems). All users have the same permissions/access to the organizational
forms library.
Any ideas what may be causing this or how I can fix it?