Btw, there were some logic glitches in the first draft, this is the draft that actually works (you also have to apply the fix jcl mentioned above):
Code:
function hourOpen(int hourblockstart, int hourblockend)
{
	//blocks new open trades between selected hours
	//uses NYSE time, including DST
	if ( (lhour(ET) >= hourblockstart) && (lhour(ET) <= hourblockend) )
		return 0; //between blocked hours, do not allow trade opens
	else
		return 1; //no conditions met, allow trades by default
}