Thanks to Paul Souza - he found a work around for the crashing face detect on certain systems. It seems to be related to a specific Haar cascade file (haarcascade_frontalface_alt.xml).  These files represent the result of Haar Training (A laborious process which should be automated) and are used as object detectors in OpenCV.  Paul overwrote the troublesome file with haarcascade_frontalface_alt2.xml. 

Which led to me to do something which I have been meaning to do for a while .. which is to have a selectable Haar filename...

This worked rather well.  On my system I was able to switch between the various files while a capture was in progress.  You could get a feeling of the accuracy, and speed of each of the files quite easily.

Thanks Paul !