[imp] redirect problems

[gaechr@fh-pforzheim.de]

Hey
I Installed Imp on OpenBSD and it works so far.
My problem ist when I start on the /horde/imp/login.php and enter the user and 
password he goes to the redirect.php an gives me a session ID like
(http://xxx.xx.xx.xx/horde/imp/redirect.php?
Horde=38dac0c81b0e3f6dcdb18a481a5c5a57)an the message:side could not be found.

When I replace redirect.php with mailbox.php like 
(http://xxx.xx.xx.xx/horde/imp/mailbox.php?
Horde=38dac0c81b0e3f6dcdb18a481a5c5a57)
I get my mails and everything works perfect.

Does anybody has a idear how I can fix this ???

thanks Chris