Hello Cindy,
It does happen but not very often, usually it is because the reverse button gets stuck in because there is no oil on the mechanism, you need to take the end panel off to see the mechanism or the top of the machine off, with the top of the machine off preferably check inside to make sure no screws have come loose on the reverse mechanism, you will soon see it, try some WD40 which is a very thin oil and give it a try, make sure the plug is out of the machine before you go inside the machine, any problems let me know, I can't picture this model at the moment, are you in the US ?
Ken
drivewithken@blueyonder.co.uk, July 2007