[Paraview] probe filter

[pleramorphyllactic at navigo.com]

Sorry, I think this is a simple question, but I am having trouble getting 
the probe filter to access.  I have some data that I generated using open 
foam, and (in case anyone cares or is helpful), i ran Ucomponents on the 
data to get a restirction graph.  Anyway, no matter what I do I seem 
unable to get the probe filter to become available for use on the data.  
Could someone help?

Thanks,
plera