A problem with forum registration e-mails not getting sent was recently brought to my attention, and I believe it has now been resolved. My tests have worked, but it worked when I tested before too so apparently that doesn't mean much. For some reason it was able to send to my personal domain (which is not related to this domain in any way), but not to other little domains like GMail. I have activated a couple of accounts that were pending and hopefully those users haven't completely given up on me. :-)
Let me know through SourceForge if there are any further problems with registration, and my apologies for any problems this may have caused you.