data file

Hello,

I used VMD1.9.1 and made a data file for lammps with this command:
topo writelammpsdata myfile.txt
then I used lmp_win_no-mpi.exe and tried to run my input file.
But I get this error:
incorrect atom format in data file <atomcpp:540>

What would be the problem?

Thanks,

maybe

topo writelammpsdata myfile.data