Try a DNS flush.

I had a similar problem not to long ago and a dns flush is what it took to get me back in the game.

How to do it: Click your Windows Start Button > Under "Search programs and files" type "cmd" and press enter > a black box should have popped up, type "ipconfig /flushdns" (without the quotes) and press enter.

That should be it. If this doesn't take care of your problem then I'm afraid I don't know what will.

Hopefully you'll be able to get past the character selection screen now and back to playing the game.