[imp] Access to other users mailboxes

[Myke Place]

We've got a serious problem that I could really use some help with. 
Apparently, some users are logging into our IMP installation and getting 
the mailboxes of other users. 

I see in the logs that IMP is contacting the IMAP server and logging in,
but on the Inbox screen, another users mail is displayed. We are using 
phpa with the follwing versions:

Horde: 2.2.1
IMP: 3.2.1
PHP Version: 4.2.3

Does anybody have a clue what might be going on? It doesn't happen with
every user, only occasionally. This is very disturbing.

-mp

-- 
I think computer viruses should count as life. I think it says something about
human nature that the only life we have created so far is purely destructive. 
We've created life in our own image. -Steven Hawking