Click to Go to Web Page - Access of Undefined Property Window

Forgive me if this is a stupid question with an easy answer.

All I’m trying to do is link a button to a webpage using HTML5. The code snippet is attached, I’ve not even changing it yet. For the Record, ‘Use Advanced Layers’ is turned off.

The code hasn’t changed:

this.button_1.addEventListener("click", fl_ClickToGoToWebPage);

function fl_ClickToGoToWebPage() {
	window.open("http://www.adobe.com", "_blank");
}

I’m still getting the ‘Access of Undefined Property Window’ message when I export.

What am I doing wrong?