Gmx mmpbsa

Problem with gmx_MMPBSA----> I gave the following command:
gmx_MMPBSA -O -i mmpbsa.in -cs full_mdp.tpr -ci complex.ndx -cg 1 14 -ct trj.xtc -cp topol.top -o final.dat -do final2.dat<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<< but I obtained this error CalcError with REC.prmtop!What is this problem ? In addition
I used charmm-gui and gromacs for simulations. Should I have converted the topology file or some other file? Or does the command do it automatically?