Digital BW, The Print

I have a friend I'm trying to help with 3800 problems, since I don't have one, nor am very familiar with them, I will paste her descriptions in hoping someone here might be familiar... thanks.
Tyler

her comments follow-

"the rear feed is not sensing there is paper there even
though the top sheet feed and the front one works. I took it back, but
the guy is saying that since it has a new feed assembly there is
nothing else to do and that he thinks it is my paper.  I've been using
Hahnemuhl paper for years."
"  I found last night that the rear feed in question
will take the paper if it is very thick as Museo 300 or Photorag 308
(but only the back side up with the photorag) and also William turner
with back side up.  I guess this has something to do with the way it
is cut?  also, I must click on "print" first.  didn't have to do that
before.  I guess I will try some other papers.  Possibly if I tried a
double-sided paper? It was a little fussy before, but not anything
like this!"
"I called Epson and we went through the cleaning process, etc. to no avail.  And they are putting it back onto  the repair situation. They think it has something like optical sensor not working."
"It is that the rear feed will not sense that there is paper there (except for Museo Portfolio Rag -- of the thick papers I have to try).  Or it sometimes will try to take HPR, but only the back side.  No noise like it is trying.  No nothing."