If you are doing something in your picture the IPR rendering option doesn't support, for instance ray-tracing, it will not render. You should get an error message in the status bar as well as one in the script editor I believe
Red bellows of flame have blackened my stones
Convulsing my frame and cracking my bones
Hell's dragons of steel who roar in their chains
Crawl into my caves to suck out my veins.....
-The Mountain P.F.M.