Bug tracker
Registration username check against the Word Censor is incorrect (fix completed in vcs)
The check done at registration time of the username against the Word Censor table is doing a partial string match and not a word match.
As a result registrations are being denied because the username contains a partial string that matches a "word" in the Word Censor Table.
The problem statement is in funtions_user.php
if (preg_match('#(' . str_replace('\*', '.*?', preg_quote($row['word'], '#')) . ')#i', $username))
My own feeling on this is that registration should not check the Word table anyway (it is supposed to be a posting function) - particularly as the disallow usernames function allows the entry of words with leading and trailing wildcards.