Previously, all meeting requests for a partner were forwarded to his
secretary's calendar, no schedules were kept on his own calendar. When the
secretary left, I set the partner up to use his own calendar. The
secretary's user account has been deleted. When a meeting request is sent to
the partner now, the sender receives a bounceback because the secretary's
user account no longer exists.

I've verified that there are no rules in his Outlook client, and that there
is no forwarding setup on the Exchange server.

This process was setup by the previous sys admin, when running Exc 5.5,
Outlook 2k on NT4 domain. In the 2 years I've been here, I've migrated us
through E2K and W2K Server using AD and now onto E2K3 and W2K3 using O2K3.

Where else can I check to resolve this. Everytime someone sends him a
meeting request, they get a bounceback from a user that is no longer active.