Hi. Probably another late-night blindness, but can someone tell me why the Short trade isn't entered in this simple script?

Code:
function tmf() {
	for(open_trades) {
	}
	return 0;
}

function run() {
	set(HEDGING);
	set(LOGFILE);
	set(PARAMETERS);
	set(PLOTNOW);
	set(PLOTPRICE);
	set(TICKS);
	
	BarPeriod	= 240;
	StartDate	= 20130101;
	EndDate		= 20130331;
	
	if(NumOpenTotal==0) {
		enterLong(tmf);
		enterShort(tmf);
	}
}


If I comment out the empty for(open_trades) loop in the TMF, the Short trade is entered...

Thanks.