I'll give you the same advice I've given the last two dozen people who've asked the same question.
Go to the Wizard's Tower and Download the Ender's client: viewtopic.php?f=27&t=14575
http://www.mediafire.com/hnh_enderThe Ender's Client is superior to the default client in every manner and, on top of that, it's also better supported and has a larger body of knowledge to pull from. If you run into problems with Ender's, then consult the Problem Shooting Flow Chart: viewtopic.php?f=27&t=12278