We use a number of custom forms that worked perfectly in Outlook 2003. When
we migrate to Outlook 2007, however, the control is replaced by a large red X
where the control should be.

If the page is opened in Explorer the control loads fine. I beleive this to
be a permissions or security problem but I cannot find where or what to
change to allow this control to run. Someone told me it has to do with email
being rendered in Word instead of Explorer.