The first error means that it isn't even getting as far as printing out the "Content-type" and other HTTP headers. That usually means that it's crashing before it gets anywhere. Are you sure that the PHP you compiled runs properly? You can run it from the command line to see.

The second error is probably just that it tried to find an HTML file for the error besides the one compiled into Apache. Almost definitely not anything that has any bearing on your initial problem.