[Exim4U] can't add domains

Hi, i installed exim4u on arch linux. i got a working exim setup, but i can't add domains to the mysql database. i logged in to the exim4u web interface with the siteadmin user and changed the password, which got written to the users table. but when i try to add a local domain, i get a blank page. no errors are printed to the http server log, only a couple of warnings ( http://sprunge.us/aETF ). there are no errors in the mysql and exim logs either. the mail folder is /home/exim4u/mail and owned by user exim4u(150) and group exim4u(150). permissions on the folder are 775. any ideas on how to debug this ? thx in advance, Norbert Lechner