[imp] 3.2.x - multi-page (&page=1) bug?

[Paul.Reilly at tcd.ie]

I'm runnning IMP 3.2.1 with Horde 2.2.3 and PHP 4.3.1 see the following
problem:

When a mailbox has more messages than than the user has chosen to display
on one page, it comes back with:

 [ALERT] Fatal error: Invalid argument

If you append, '&page=1' on to the URL it works fine.
As does clicking forward to the second page of messages, and
then back to the first. I looked through mailbox.php and
it does know which page it's on etc, but it doesn't add
add &page=1 to the query string.

I thought it might be fixed in 3.2.2 but that seems to be the same.
Any pointers on where to look to fix this?

Thanks,
Paul