on(map, "load", lang.hitch(this, function(){addGraphic();}));
1. Define the polygon spatial reference before you add the ring
2. alert (thisLocs) right before you try to use it. My guess is this is a scoping issue and it is null
try changing the line toon(map, "load", lang.hitch(this, function(){addGraphic();}));
on(map, "load", lang.hitch(this, function(){addGraphic();}));