WARNING message has occured when use parallel processing to compile.

warning messages:


Setting up run ...
175 mesh elements have high aspect ratio (angle < 0.500000 °)
WARNING: Mesh contains highly skewed element (multi_node_mesh_parallel_I.h:513)
Import and parallelization of mesh cad containing 1448 triangle(s) successful
149 mesh elements have high aspect ratio (angle < 0.500000 °)
WARNING: Mesh contains highly skewed element (multi_node_mesh_parallel_I.h:513)
Import and parallelization of mesh cad2 containing 10288 triangle(s) successful
INFO: Resetting random generator for region bc
Memory usage per processor = 11.1755 Mbytes


This message appears when i try to use parallel processing ( e.g. mpirun -np 8 ) but if i use single core it has no problem.
Can you give me a easy description for this warning message? What does it mean?