MG preconditioner issue

[Matt Funk]

Hi,

i am trying out the MG preconditioner in PETSc and am encountering some 
issues. In fact when i use the MG preconditioner i get a segmentation 
violation. This does not happen with other preconditioners.

Running Petsc in debug mode with the -info option did not seem to produce any 
useful data (at least to me)

I thought i'd ask if someone encountered this before i use valgrind. I am 
using 2.3.3-p8. Or does anyone have a hint on where i could start looking? 
Again, what bothers me is that the other preconditioner do not throw any sort 
of error.

thanks
mat