I know recently, due to changing webhosts and so on. we had an issue with registering. This i thought was fixed, but i found a new much bigger problem with the code base we used before. It's not very interesting to go into it so i wont. But it's forced my hand in changing the forum codebase to phpbb3. Which i don't plan on changing any time soon. I have a few more things to do on the forum, but my main aim was to get it up and going for everyone. So ta da! there you have it.
I know re-registering is stupid and annoying.. But the conversion between the two databases wouldnt be possible and would create too many issues.