md simulation protein-ligand complex

Question

[Sarah Diana]

Hi,

1. May I know what this error means? What should I do to fixed it?

   Fatal error:
   
   Index[3336] 3337 is larger than the number of atoms in the
   trajectory file (3336). There is a mismatch in the contents
   of your -f, -s and/or -n files.
   For more information and tips for troubleshooting, please check the GROMACS
   website at http://www.gromacs.org/Documentation/Errors
   

2. I already done the rmsd but I don't get the stable rmsd graph can u suggest some thing that I can done or mistake that I done that I got unstable rmsd graph?