[gmx-users] Teethering/ Fatal error when using posre

[Joanne Hanna]

Hi 

I am getting this error when trying to grompp my files:
Fatal error: [ file "posre_lig.itp", line 5 ]:
Atom index (5214) in position_restraints out of bounds (1-20)

I do not know what this means or how to fix it, i have generated my posre files for my protein and three ligands using genpr. these are defined in the *.top files by using an ifdef statement and in the *.mdp i have defined -DPOSRES.

can anybody help point me in the right direction?

Thanks
Jo