Easy Alert component question

Hi. I’m having problems with this extremely simple bit of code, and I have no idea what is wrong, even after reading through the Flash reference.

mx.controls.Alert.show(“My message”,“My title”,Alert.YES | Alert.NO,null,clickHandler, null, Alert.YES);

The Alert displays, but does not display my two buttons Alert.YES and Alert.NO, only an OK button. What’s wrong??