We have exactly the same problem!
opened the bottom freezer section, theres plastic rivets holding the back panel (inside) once off theres the packaing foam stuff and behind that was a tonne of ice, once all melted with a steam gun and resealed it worked ok for a while and then did it again.
just bought another fridge today and willplay wiht the brandt to see what happens..
if you find a perm fix please email me! liaquat @ h o t mail . c o m!
Liaquat
September 2008