Compass issue

I am running android with sdk 1.8.1 on a mac in the emulator and on my buddies device (I can't remember what device that was other then it was an HTC) I am getting the following error in ddms every time i uncomment the following code.

02-13 20:52:28.385: E/TiSensorHelper(997): (main) [800,185986] unable to unregister, sensorManager is null

Ti.API.info('running once')
Ti.Geolocation.getCurrentHeading(function(e)
        {
            if (e.error)
            {
                alert( 'error: ' + e.error);
                Ti.API.info("Code translation: " +e.code + ';' + e.error + ';' +  translateErrorCode(e.code));
                return;
            }
            var x = e.heading.x;
            var y = e.heading.y;
            var z = e.heading.z;
            var magneticHeading = e.heading.magneticHeading;
            var accuracy = e.heading.accuracy;
            var trueHeading = e.heading.trueHeading;
            var timestamp = e.heading.timestamp;
 
            Titanium.API.info('geo - current heading: ' + new Date(timestamp) + ' x ' + x + ' y ' + y + ' z ' + z);
        });

It keeps running over and over even though it is supposed to only run once. I keep getting the "current heading" but running once only shows once. The callback is still commented out later in the code.

Any ideas?

I've had the same problem (on IOS though), so I include a var hasGotHeading = false that i set to hasGotHeading=true once ive got the value i'm after and ignore any later events