function isNullWindow(win) {
	if(win === null || win.focus === null)
	{
		var text = "This site uses POPUP windows.\n\n";
		text += "We were not able to pop up a window to allow you to view this content.\n\n";
		text += "Please make sure you are not running any popup blocking software.\n\n";
		text += "If you are, please turn it off and restart your browser.\n\n";
		alert(text);
		return true;
	}
	win.focus();
	return false;
}