Unalbe to open additional mailboxes

[Aran]

I am able to use the file|open option, but not by adding
the user to the "open these additional mailboxes. I keep
getting the error "unalbe to expand the folder. The set
of folders could not be opened"

I am using outlook 2002 and the mailboxes are both in the
same storage group with exchange 2000.

Thanks in advance for your help