How can I fix a leaking dishwasher?

I have a Hotpoint DWF30 dishwasher and this morning when I used that water had leaked from somewhere as there was a puddle on the floor in front of the machine.

I have checked the cold water fitting and the drain hose and neither of these are leaking and both were dry when I pulled the machine out to have a look.

Is this a common problem/fault and do you have any ideas why this is now happening?