WORKAROUND
First a disclaimer I just read this thread today and haven’t tried all the suggestions previously given. I have been experiencing this issue since the prelaunch though and have tried disabling anti-virus, and setting port forwarding to no avail.
Workaround: Whenever I am on a skype call or downloading a large file Guild Wars 2 runs flawlessly. As soon as the call ends or the download finishes I lag out and receive the 7 error within 5-10 minutes. Hopefully this workaround works for others and/or leads ArenaNet to the root of the problem. Let me know if it works for you.