AEG Favorit40010V1 door pops open - drainage issue help?

We have a 2.5 year old AEG Favorit40010V1 dishwasher that wont complete its wash cycle as the door pops open mid cycle.

If you close the door, it pops open again after a very short time - typically every 10Secs. The programme was forced to the end of the cycle (by me holding the door closed) and it pumped all the water out at the end of the cycle suggesting no pipe blockage.

I thought it was probably a drainage issue. I have checked both filters and they are clean.

It has happened before over the last few weeks and the door has popped open and when shut again it has gone through to the end of the cycle.

I thought maybe it was a blockage that has now cleared itself but this doesnt now make sense?

Any bright ideas?

Thank you in advance.

Liam
September 2011