Mesh import problem "ERROR: Mesh elements have been lost".

error message

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LIGGGHTS (Version LIGGGHTS-PUBLIC 2.0.7, compiled 2012-08-25-16:06:53 by spe based on LAMMPS 20 Apr 2012)
Created orthogonal box = (-0.85 -0.08 -0.08) to (0.01 0.08 0.14)
1 by 1 by 1 MPI processor grid

Reading STL file 'barrel.stl'
Solid body detected in STL file
End of solid body detected in STL file.

Reading STL file 'screw.stl'
Solid body detected in STL file
End of solid body detected in STL file.
Fix particledistribution/discrete (id pdd1): distribution based on mass%:
pts1: d=2.000000e-03 (max. bounding sphere) mass%=30.000000%
pts2: d=3.000000e-03 (max. bounding sphere) mass%=70.000000%
Fix particledistribution/discrete (id pdd1): distribution based on number%:
pts1: d=2.000000e-03 (max. bounding sphere) number%=59.124088%
pts2: d=3.000000e-03 (max. bounding sphere) number%=40.875912%
0 atoms in group nve_group
Setting up run ...
Import and parallelization of mesh cad containing 4410 triangle(s) successful
ERROR: Mesh elements have been lost (multi_node_mesh_parallel_I.h:508)
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I checked it and quite confident this problem is about STL file. On previous version of LIGGGHTS normally when i made meshes and imported mesh models to DEM. i was stuck error messages about confliction point of triangular in STL file (and error messages tell me which line is conflict) and when removed all problem lines in STL file every thing it was done. but in this case the error messages don't tell me about conflict line but tell me some error problem like this "ERROR: Mesh elements have been lost (multi_node_mesh_parallel_I.h:508)"
Do you have any ideas about this problem?