Well as a novice user of both mysql and php, I've set up quite a few minibb's by now on my netware server.
It works like a charm, as long as the right php version is used (Novell didn't implement all functions for some reason), so I can assure you that it's not in minibb the problem is, it's either 40 cm in front of the screen, or 40 cm below the screen :-)
Seting it up do take some time, but that's mostly because the mysql has to be configured first, and it has to be correct and in working order (phpmyadmin is an easy way to check this out).
Then the scripts has to be set up to reflect the site properly.
After that, there isn't much more to do.
P.S. No to avatars, go use phpbb instead for that.