Whats wrong with my hotpoint dwf50 dishwasher?

I have just replaced heater element because the power kept tripping now when I try to run the machine it starts to pump out first then starts to fill for about 30 seconds and stops. The eco and prewash lights are flashing along with rinse aid. According to crazysquirrel.com this means the filter is blocked but I have cleaned them and even run the machine with them removed but still same result.I have removed all the different hoses and blown through them with no sign of a blockage. I have also removed the salt container and flushed it through, removed pump and checked impeller but still same result. I'm now on the verge of selling my soul or turning to alcohol. Please can anyone help with a solution either that or a bottle of vodka ;-). Cheers.