FLVPlayback produces error when moving to other frame

Question

I have an FLVPlayback component video and I've selected through it a source file which is in the same directory as my fla.

The source file is a .f4v file.

The instance name I have given the video is phi_int .

I also have a back button which takes me back to a certain point in my timeline.

The frame of the video is 882 and the back button takes me to frame 360. In the action of the back button I have included the following function:

function backclickFunction2(ev:MouseEvent):void
{

    phi_int.stop();

    removeChild(phi_int);

    gotoAndPlay(360);
}

When I press the back button I receive the following error:

TypeError: Error #1009: Cannot access a property or method of a null object reference. at EurognosiFlashApplication2_fla::MainTimeline/backclickFunction2() [EurognosiFlashApplication2_fla.MainTimeline::frame882:7] [UnloadSWF] Eurognosi%20Flash%20Application2.swf

Any ideas?