I think it's been fixed. I lost out on a Library Quest earlier due to the same reason, but the site was having major hiccups. Haven't seen that error since the issues stopped.
that was probably when my inventory was showing nothing in it and there was a database error or something going on on most pages >.> I haven't noticed it for awhile though. too bad you missed out on a few quests though :(
yeah it should be working now, I've seen no signs of the glitch in the past hour or so, so I think you're safe to do quests :)