Outlook 2003 and custom contact forms

[Argy]

We just started using outlook 2003 with exchange 2003.
Previously we were using outlook 2002 with exchange 2000
with no problem.

The error that we get is with custom contact forms. We
use a spare mailbox to share our contacts within the
organisation. This contact folder is using a custom
contact form. When doing a search and then selecting a
contact we get the error "Can't open this item", then if
you clear the search and scroll down to the contact and
then select it, it will open with no problem. If I close
outlook, and then re open, the problem will disappear for
a while.

Any ideas would be appreciated.