I'm really glad you posted this, because I'm having a similar problem. Despite having played Guild Wars for many months without issue, the most recent update has stopped me connecting at all. Even more bizarrely, if I run it in a window, I see that when I click "connect" on the logic page, it actually disconnects my wireless network!
I can run any other game, no problem, play it online etc... can do anything on the Internet, but (completely replicably every time) when I try and run Guild Wars and connect, it disconnects my wireless network and thus error 7's!