Black screen?

Hi all,
I just compild the 1.7.1 code without errors, loaded up the template game, and got a black screen.
the log reported no errors, there is sound, and I believe action, because hitting F11 brings up the editor and displays everything fine.
exit back to game and black screen.

now I ran the same demo before I compiled, it ran fine. compiled it, black sreen.

any ideas??

thanks