This is just a suggestion.... so please try and please post any corrections.
Anthony M is on the right track. Refer to his entry and download the manuals. Tks Anthony. When the Dishlex 300 starts for the first time, there is a service mode set up. The service mode allows you to set a 'fill-time' for the water to reach the right level, dependent on the water pressure and flow... which is described in the manual. So resetting the Dishlex is the first step. Then set the water level. If the water is too low, it will not wash, it will flash. When the water is too high, it will leak out of the rubber seal.
I hope this helps you all. Waz