This is probably caused by the server owners not having updated to 1.8.1 or other problems they are having so its not yours because I got a similar problem but really its nothing to do with us its the server owners...
So yeah you'll have to just wait until they are available or just go back to 1.7.3 and see if they are still using that or go to their websites and see whats going on.
@Woods Problem Solved /server sided problems...