First of all, you guys are doing a great job... :)
After I setup the latest stable release on my web server I tried to login with no errors. 
I'm currently using only one database that contains the tables for a phpbb, a gallery and the webmail. 
I had no serious problems, but after some playing around the webmail became more and more unstable. 
Sometimes I'm getting the "SERVICE CURRENTLY NOT AVAILABLE!" error while browsing and when I switched over to my board or gallery I got the message; "Can't connect to database...max_user_connections". 
After I removed the webmail from my server everything was fine after a short period of downtime (I couldn't even access phpmyadmin at that time). 
Does anyone else have this kind of problems?