[gmx-users] How I can create a gromacs input file from a gamess output

[Marcelo de Freitas Lima]

Please,

I 'd like your help to create a input file (.pdb, .gro,etc..) from a 
gamess calculation result.
I converted a xyz file from the z-matrix in gamess output to pdb with 
openbabel,
but when I run pdb2gmx, the result is:
"Fatal error: Residue 'UNK' not found in residue topology database"

Thanks,

Marcelo Lima using Gromacs 3.2.1 with debian woody-linux and only 1 cpu.
P.S. I started in Gromacs a few weeks ago, I read the Gromacs manual, 
but I can't see any answer for me.