hi!!
I think there is a mistake in the example of .mesh given in the help 'pdf' i found on http://brainvisa.info
I think the normals associated with a mesh which polygone Dimension is 2 must be a vector which size must be 3 * number of vertices and not just one 0 like in the example.
I tryed with 3 * number of vertices of 0, and it works.
Actually normals are optional in .mesh files, so it's valid to have a mesh with 0 normals. But if they are not 0 then there has to be as many normals as vertices.