A little more info may help. Have you read all the stickies and made a search in the forums? Maybe someone else had a similar problem. What's your OS? You might want to take a look at the linux or mac support forums if you are using either one of those. Have you read the stickies? Also make sure you have the latest client version (v4.0). Let us know if none of these problems matches yours.
Well, I'm not very knowledgeable when it comes to the technical part but I can poke someone who might be. Being specific helps a lot.