When a simulation with bond constraints is started, DL_POLY_2 attempts
to extract the kinetic energy of the constrained atom-atom bonds
arising from the assignment of initial random velocities. If this
procedure fails, the program will terminate. The likely cause is a
badly generated initial configuration.
Action:
Some help may be gained from increasing the cycle
limit, by following the standard user response to increase the control
parameter mxshak. You may also consider reducing the tolerance
of the SHAKE iteration, the directive shake in the CONTROL
file. However it is probably better to take a good look at the
starting conditions!