In the user function load_spins() in generic_fns/structure/main.py a check whether the residue name exists or not has been included. The code is similiar to the molecule check. Also see email: https://mail.gna.org/public/relax-devel/2011-06/msg00226.html. And in the system test 'test_read_xyz_internal2()' all models were loaded instead of 2 and the line for loading proton was removed.