There is a little drain pipe which let drive the condensated water outside and the water should freeze in the pipe if you let the door open. This is causing that icing up and dripping.
The solution should be if you leave the freezer switch off for two days or more with open door or remove the inside plastic cover and try to find the little pipeline and defroze it. Not a NASA technology, the bigges challenge should be how to remove the cover.
Never leave the door open, because the problem should come up again.
szabolcs.hu, August 2012