post processing error

The following message occurs while running the post processing module -

$ postproc.py its2D.vtk

WARNING: Imported VTK version (5.8) does not match the one used to build the TVTK classes (5.6). This may cause problems. Please rebuild TVTK.

Traceback (most recent call last): File "./postproc.py", line 8, in <module> from sfepy.postprocess import Viewer, get_data_ranges, create_file_source File "c:\src\sfepy\sfepy\postprocess\__init__.py", line 1, in <module> from viewer import Viewer, ViewerGUI File "c:\src\sfepy\sfepy\postprocess\viewer.py", line 33, in <module> from sfepy.postprocess.utils import mlab File "c:\src\sfepy\sfepy\postprocess\utils.py", line 14, in <module> mlab = mayavi.mlab AttributeError: 'module' object has no attribute 'mlab'