GW2's Twitter: Follow Guild Wars 2 about an hour ago:
We have re-established server connectivity and are aware of some Error 42 issues.If you find this error please try again to reconnect. ^DO
and then again about 15 minutes later:
If you're getting an error 42 trying to log in to #GW2, try closing and relaunching the client. Thanks for your continued patience! ~RB2
still not getting in though...