Are you using custom forms in Outlook 2003 and they aren't working, yet work perfectly in Outlook 2002?
Outlook 2003 includes a new setting which is turned off by default that allows forms in shared mailboxes to run scripts.
You can change the setting by choosing Tools | Options |
Other | Advanced Options and checking the box for Allow script
in shared folders. There is a box for script in Public Folders
here too.