This was apparently causing some errors on windows machines...

			previewsContainer: '#null',

			clickable: false,

			accept: function ( file, done ) {

				if ( file.type !== 'application/json' ) {

					alert( 'Whoops, make sure you upload a .json file.' );

				} else {

				stageTwo( file );

				dropzone.disable(); // Your job is done, buddy

			}

			}

		} );

	}