it sure is a drainage problem, it means the pump impellor isny turning, probably a blockage, as pumps usually dont jam for no reason.
Try removing the filter parts and having a poke about down there, i use a length of net curtain wire, about 8 inches long! sometimes doesnt work straight away but keep trying and eventually you will dislodge whatever is stuck and it will pump through the drain hose never to be seen again - perfect!
Jason, July 2007