ExportMED() function does not work when running with "-t" option

Hello,

I made a script that constructs a mesh. I have included the following code to export the mesh in .med format:

try:
  Mesh_1.ExportMED( r'./meshMed.med', 0, 40, 1, Mesh_1, 1, [], 'ev',-1 )
  pass
except:
  print('ExportPartToMED() failed')

When I run this script by "salome name.py" or "salome -t name.py" (batch mode) the mesh is not exported and the message   'ExportPartToMED() failed' is printed. I have not this problem when I try to export the mesh in .unv format.

Any idea?