If you're hit with this error and it's because of a California Form 568, the way to fix it (and have both Federal and State returns eFiled successfully online) is to remove just form 568 from TurboTax. I found a really easy way to do it.
(1) Save / print a copy of Form 568 from TurboTax, so you don't have to reproduce it for later for when you send it in by mail.
(2) Go to the question in TurboTax where it asks whether you have only a Single Member LLC. Say "NO," even though the answer is yes. This will remove Form 568.
(3) eFile again, submitting both state and federal. Both will now be accepted.
(4) File Form 568 by mail.
