Intermittent error in traits

This code gives an intermittent error with vtk > 6.3
```
from mayavi import mlab
import numpy as np

my=np.array([[1,2,3],[4,5,6],[7,8,9]])
plotme=np.log(my)
plotme[np.isinf(plotme)]=0

mlab.figure(bgcolor=(0,0,0))
src=mlab.pipeline.scalar_field(plotme)
mlab.pipeline.volume(src)
mlab.pipeline.image_plane_widget(src,plane_orientation='y_axes')
mlab.xlabel('E')
mlab.ylabel('mu')
mlab.zlabel('P')
mlab.outline()
mlab.show()
```
traits.trait_errors.TraitError: The 'vector_component' trait of a SmartVolumeMapper instance must be 0 <= a long integer <= 3, but a value of 1750425008 was specified.
The number is not always the same and some times there is no error.
Changing to vtk 6.3 fixes the problem and it occurs in python 2 and 3. This is code cut down to show the error.
I also tried similar code in fedora rawhide which is the only one with vtk7.1 as yet.