Silent, nothing has happened to your forum. The MySQL Error is all over the server. It's an error message that is consistent with the Webmaster working on something, with the server still online, but it has been like this for so long now, that I'm becoming more inclined to believe that the server got stuck like this, all by itself.
The problem is any case reported to the Webmaster, and he will deal with it as soon as possible. It may take a while for him to find the message though, as we are in the middle of the night here in Europe...
FoxLeonard