Hopefully this is the same problem that I have had.
Is the URL now redirect.php ? (when on the blank screen)
Does hitting refresh help?
If you check your 'messages' log file you might have:
httpd: PHP Warning: Failed opening 'Log.php' for inclusion
(include_path='.:/usr/share/pear') in /home/httpd/html/horde/lib/Horde.php
on line 145
httpd: PHP Fatal error: Undefined class name 'log' in
/home/httpd/html/horde/lib/Horde.php on line 155
If this is the case you are missing Log.php from /usr/share/pear
the blank screen at IMP log-in can be solved by installing this from
http://pear.php.net/package-info.php?pacid=8This is package just needs expanding and putting into /usr/share/pear.
After this it worked fine for me.
regards
Ian