[gmx-users] error

[CORINA BARBU]

Hello gmx-users!

I try to run a simulation on a molecule which is NOT a protein(or other
biomolecule). No matter which of the ff implemented in gromacs I choose the
result is this:

"Fatal error: Residue '' not found in residue topology database."

I kind of expected it, I imagine that these ff do not have defined at least one
atomtype that I need for my molecule.
 
Where from to start fixing the problem? 
 
Does one really need the residue topology database? 

Or what's the matter?

Thanks! Corina