Originally Posted by
blitzen
I have the LH flight reference it works on LH - but when I then hit check-in it opens a browser back to AA
Correct. - Because up until your AA flight is closed, the control of the ticket and Check-in is with AA.
Originally Posted by
blitzen
the airport AA rep flew through FRA before and said going to LH to check in and get a boarding pass is the normal procedure
This is not the normal procedure. - Technically both airlines have interline agreements in place and AA should be able to check you through to LH.
If they cannot yet issue you an LH BP, then make sure that they do at least check your bags through to the LH flight.
(If you still have time: try to get a supervisor or the like involved)
Just to double-check: you have one ticket number, this ticket number is starting with 001 and both AA and LH flights are listed in there?