But he said he entered the words down on paper very carefully. but people are insisting he made a mistake. that doesn't make any sense. those two things don't jive. i tend to believe him that he did write them down correctly because he insisted that was the case not just once but twice in this thread.
I've already covered all the possible scenarios that I can think of in my initial comment in this thread. I can't think of any other reason for this happening and unfortunately Electrum UI doesn't provide proper error messages to user to know where exactly the problem is coming from.
As LoyceV said it is very unlikely for Electrum to have a bug in this case, the seed class is pretty straight forward.