[gmx-users] grompp error message

[Jodi Fangman]

David 
Here is the full grompp output including the error.
Jodi

grompp -v -f em -c salt -o salt_em -p 1ubq

creating statusfile for 1 node...

Back Off! I just backed up mdout.mdp to ./#mdout.mdp.5#
Warning: as of GMX v 2.0 unit of compressibility is truly 1/bar
checking input for internal consistency...
calling /usr/bin/cpp...
processing topology...
Generated 241860 of the 241860 non-bonded parameter combinations
Generating 1-4 interactions: fudge = 0.5
Generated 241860 of the 241860 1-4 parameter combinations
Excluding 3 bonded neighbours for Protein             1
Excluding 2 bonded neighbours for SOL              4513
Cleaning up temporary file grompp000318
Fatal error: No such moleculetype NA+