Hotpoint aquarius - prewash lights flash?

Once i switch it on it works well, 10 minutes later it stops and the prewash light keeps flashing. Ghen i on the washing machine the lights that come on are 'door locked' and 'wash' it doent get past that. i keep switching start and it repeats the same after 10 minutes. the problem continues if i select rince and spin it ends up with the prewash light flashing.
Can anyone help please?