@Dorque: When the website was updated to support the new FS2NetD code it was for the old server. Now everything has moved to a new server and the old setup that I had is no longer valid. The error you mentioned was reported and fixed earlier, so give it another try and report back if it still doesn't work for you.
FS2NetD is back up, but still in a sort of testing mode so that bugs can get worked out. Feel free to play as normal, just be prepared for a few hiccups while we work out any remaining problems. After the testing phase there should be some sort of public announcement letting everyone know that FS2NetD is back up, at which point you'll know for sure that it's safe to play again (if you don't want to use it in the meantime).