As it seems, for the last couple of days the registration on compojoom was not possible. I'm really sorry for this! The problem was caused by our new friendly SEF urls and the rewriting that our SEF extension was making. Thank to a user that pointed this out, we've fixed that and you will be able to register.
I wish to use the occasion to ask you to report every single problem that you find on compojoom! We take this very serious and try to fix everything immediately! Thank you!