The actual bug report process is on trac, you get there by going to http://developer.wz2100.net
and hit the login link.
Then you enter your forum name & password (case sensitive).
Once you are logged in, then you hit the http://developer.wz2100.net/newticket
link, and it will take you to a entry form where you enter all the details.
Normally, that is the place we want all bug reports to go, and with enough information so that we can replicate and eventually fix the issue in the bug report.
In this case, since not many people play these builds, and if you are unsure if it is a bug or not, then this thread comes in handy.
If you have a way to replicate the issue, then trac is better, since it does send out a e-mail to everyone about the issue.
Hope that clears things up.