Dishwasher anti-flood device & reasons why it might be activated

Hi,

I have an integrated dishwasher & the anti-flood device was activated.

Thanks to boards.ie I reset it by tipping the dishwasher & draining the water out onto a towel.

Problem is though that I have had to do this every 3 or 4 washes.

Can anyone tell me where this excess water may be coming from?
Thanks

Edit: I should mention that it seems to drain fine but there is evidently excess water left behind in the sump.