[gmx-users] moleculaes breaking off after EM - help

[Thejus Kartha]

Greetings!
I was performing an EM run with an array of dioxane molecules, for which I had produced co-ordinates from PRODRG. I got the co-ordinates, and made an array of it, using the gmx genconf module, and corrected my topology file. Then, I thought I should minimize the energy of this array before solvating it, or anything. So, as I was running the grompp module using mdp files from Dr. Lemkul's tutorials, it gave me the following error:
Steepest Descents converged to machine precision in 641 steps,
but did not reach the requested Fmax < 1000.
Potential Energy  =  2.6059185e+09
Maximum force     =  8.6477500e+04 on atom 557
Norm of force     =  7.7685435e+03

I am presuming there's something seriously wrong with my input files, as I've been told many times before. That said, how do I tweak around with my mdp file in this case? I mean, there's this Fmax value that I have to deal with. How do I know if I am using the right threshold for Fmax? Do I base this value on information from literature? And of course, when I open the .gro file after the EM, I find my molecules to be smashed to smithereens. There are points and broken triangles flying around in all directions (dioxane is a hexagon, and it has broken to half.) Why does this happen? Please help me.
Thanks & Regards,Thejus R. KarthaM.Sc. ChemistryCentral University of Tamil Nadu