I ran the same model under both 6v2 and 7v7; it ran OK under 6v2, but crashed under 7v7. The source file was an NMR structure (1MO8) of a protein with bound ATP. Not long before the program crashed, it gave the following warning message under 7v7 which had not appeared under 6v2:

openf5__224_> Open       14  UNKNOWN  SEQUENTIAL  pmca2.rsr
TOP_________>   219  166 SET RESIDUE_SPAN_RANGE = -999 -999, RESIDUE_SPAN_SIGN = O;
                      N
 
top_mod_451W> Requested schedule step not available:        0
              SCHEDULE_STEP set to N_SCHEDULE.

Somewhat later it crashed with the error message:

nselat__596E> Atom index is out of range (iatm,natm):     1640     1639
recover____E> ERROR_STATUS >= STOP_ON_ERROR:        1       1

Any help would be appreciated.
John Penniston