Had this error multiple times before as well - and have submitted a bug report on it.
I really hate that bug, because it essentially it makes the game unplayable for me. It is really frustrating not knowing when the game will suddenly refuse to let you progress. I think the only solution is to disable autosave and hope to complete the game really quickly after that (before hitting another bug). As that is not an acceptable solution to me, I have stopped playing altogether and hope it will be fixed in Beta 4.