Hello Dear MS users,
I try to calculate the energy of ethane C-C single bond breaking. I use DMol3 with functional GGA/PBE and basis set DND. The following is error in my output file.
 
  ####ERROR####
 There should be  1 Constraints but none found on OPT file!
 Peak memory usage: 218952 kB on current thread
 ... Calling mpi_abort ...
Errors from parallel task 3:

  ####ERROR####
 There should be  1 Constraints but none found on OPT file!
 Peak memory usage: 225020 kB on current thread
 ... Calling mpi_abort ...
Errors from parallel task 4:

  ####ERROR####
 There should be  1 Constraints but none found on OPT file!
 Peak memory usage: 212880 kB on current thread

How can I solve this problem? 

Thank you very