Are you saying that the stencil is not working when you render?
If so, it’s probably an issue with pIRender (which is probably launching to do your 1080 render). Try launching pIRender manually, then click the Options button and turn off hardware acceleration. Then try your render again as usual.
(When you use an image as stencil, it’s not visible.)
Alan.
http://www.wondertouch.com