IMP is a very nice software that provides a webmail access to IMAP and POP3 servers. It is based on the framework Horde. I've been using for some time now and it always worked fine. Then, one day, after an apt-get upgrade, IMP is updated to a new version and it stopped working. In particular, I wasn't able to login (and the password was reported correctly in the system log): after a long timeout, I received as response the empty file redirect.php.
I decided to reinstall everything from scratch (Horde and IMP). Unfortunately I soon experienced problems with Horde itself, due to the default cookie directory which was '/horde', but, following the installation path, it must be '/horde3', see also this bug: http://bugs.debian.org/cgi-bin/bugreport.cgi?bug=391493. But this was solved.
The problem with IMP was still there, though! After struggling with it a whole afternoon, I came through this nice wiki, and in particular with this page, which sounded really related to my case (since I'm using UW-IMAP server). Well the problem was really that!!!
As a solution, I chose this one (which is not supported by IMP developers, but it works):
'imap_config' => array(
'children' => false,
'namespace' => array(
'main/' => array(
'name' => 'mail/',
'delimiter' => '/',
'type' => 'personal',
'hidden' => false,
'search_charset' => array(
'UTF-8' => true
It looks the problem is only due to this particular IMAP server...
I also updated a related bug report: http://bugs.debian.org/cgi-bin/bugreport.cgi?bug=383715.