Hello Bernice,
First make sure you have the needle plate on properly if it is a snap on type, make sure there is no fluff caught under the needle plate inbetween the teeth, common fault, failing that tilt the machine back and have a look at the drop feed mechanism to make sure the pin is going all the weay through the hole, you will also find a screw there where you can adjust the height of the teeth.
Ken
drivewithjken
February 2010