It means you have a problem in the return.  Either you messed up something or Intuit messed up something.  Go back and do a review of the return to see if there are any errors.  If not, try rebooting your computer and see if it flies the second time around.

Be sure youve checked the PTIN Verification box in your Firm/Preparer Information.  You wont be able to convert a file for EF until that box has been checked.