It only takes a couple of bad apples to spoil the barrel and since many people have been abusing the web-IRC client it has been discontinued.
1) install an IRC-client (for OS X you can use Conversation, XChat or Colloquoy).
2) Configure it with your username
3) use irc.convertit2mac.com for the host/server.
4) after connecting type: /join #Ultimate-Experience
5) after joining type: /msg NickServ help register
follow instrucitons to register