Your machine is designed not to spin if it cannot get rid of all the water. It certainly sounds like a blockage, and the most likely place to look is in the filter.
You need to get to the back of the machine and remove the bottom rear cover. With the cover off, you will see a black hose which goes from the tub to the pump. Incorporated in this hose is a plastic filter.When you remove the hose from the tub, a lot of water will escape. So take precautions!
Ray Thomas, March 2005
