when last was machine serviced,could be in urgent need of clean and oil or could be a problem with link between dial and needle bar.try to move needle bar left and right by hand if it does move with ease it could be the link if not clean properly area around needle bar and use good oil to lubricate all parts.there is a piece on needle bar that is connected to the moving cams that is suppose to move in and out thus moving needle bar left and right,make sure it is clean and oiled it looks like a pin moving in a tube
johan, July 2012
