Issue using JSON.stringify on object

I have the following code, which attempts to stringify the member1 object

try {

    var member1:Object = {

      mediaId: meterEvent.mediaId,

      publisherId: meterEvent.publisherId

   };

   var val:String = JSON.stringify(member1);

} catch (err:Error) {

/// exception is called

}

but this throws an exception " ReferenceError: Error #1065". I have trying to get this going for several hours but cannot seem to find a solution. I am using Falsh Builder 4.7 and the Air SDK 3.4 to compile and build the swf. I suspect that maybe the issue is that the flash player where the code is running on maybe not be compatible. The version of the Flash Player is 12,0,0,70

Any idea of where to go from here. The larger context is that i am using URLRequest and URLLoader to formulate a HTTP POST with a JSON body

cheers

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