what is wrong with my Hoover OPH 616 washing machine?

my washing machine (Hoover OPH 616) has stopped working on the wash programmes. The door locks and it will fill with water, but then it stops and one of the red lights starts to flash and it won't continue to wash. I've tried the drain and spin programmes and they're OK, but the rinse programme and all the wash cycles don't work. The filter is clear. Any ideas what it could be and how to fix it? Thanks