I don't know what your error means. Assuming there are no errors in your Surface or Alignment, but one thing you could try is doing an audit and purge of your drawing to clean up. Shutdown and restart and see if you still have the problem. I have done this with an unknown error to clear up. If this doesn't work, then I would do a repair or re-install.
from reading other forums, it sounds like a service pack issue... maybe your not downloading the right one? I found this post that someone left in February, they were having the same problem as you....http://discussion.autodesk.com/forums/thread.jspa?threadID=641158
Just in case the audit then purge doesn't work as previously suggested. Personally - the audit then purge, then reopen the drawing would be my first step.