if i remember correctly, there were two versions of the xtion pro live.
i've used them both and wondered why my stuff from the first project
didn't work on the second one. it turned out the second (newer) version
was incompatible with openni 1 (i.e. also the openni grabber
implementation and everything depending on it). hence, i had to
implement things using openni 2. (beware: i've also found some openni 2
grabber implementation in a "work in progress" branch on github or
something alike. it did not really work as well, but more because of a
faulty implementation i assume.)
not sure at all if it's of any relevance in your case, but maybe that
info helps. if you are using the openni viewer coming with the openni 2
installer, that might be a hint.