[gmx-users] grompp

[badamkhatan togoldor]

 Dear Gmx Users, 
I have a question on grompp ! 
I built some membrane in Charmm-gui with ion and water etc and i took that output data for gromacs. Then i changed xxxx.pdb file on the gromacs. Do the pdb2gmx and editconf then grompp. Unfortunately grompp gave me an error!
No default U-B types.[file topol.top, line XXXX] 
In this case what should i do?( I thought charmm-gui generated and supplied all ffbonded.itp ( .itp files was in "toppor" directory ) file for this membrane. and then i should put it that file on gromacs' ffbonded. itp file ? ) What's the wrong in here? Any help or suggestion highly appreciate!       I am using charmm36.ff . 
Thank you!  Khatnaa