The official forums have been quite fickly over the past few days. Sometimes you'll be lucky and you'll be greeted by what you're trying to look at, other times you'll get an "error500" message, and still other times you'll see a message like the one pictured above.
The plight of the official forums seems to mirror the activity on the servers. Queue (har har har) the Homer Simpson-esq: Forums go up; forums go down... Forums go up; forums go down...
The past few days of hellish lag, unstable forums, and broken parts of the game have been like the song that never ends. (Note to self: Eat some lamb chops tonight.) After four days of the patch, we're still getting a constant stream of tips detailing bugs and other errors.
I wish I could say that we'll report to you when this is all fixed, but honestly I don't think that is going to come anytime soon. Perhaps next Tuesday they'll roll out another patch to fix some of this, or change something in the datacenters, etc... It's really nearly impossible for us to know exactly what's wrong.