The dynamical shell model was not designed to work in conjunction with
constraint bonds. This error results if both are used in the same
simulation.
Action: There is no general remedy if you wish to combine both these capabilities. However if your simulation does not require the polarisability to be a feature of the constrained species, but is confined to free atoms or flexible molecules, you may consider overriding this error message and continuing with your simulation. The appropriate error trap is in subroutine SYSDEF.