i had similar problem on a different make of fridge freezer recently.
try this . remove all contents of the fridge and freezer (transfer to friend or relations fridge / freezer!) and switch it off at the mains for 24 hours. dry up any pools of water etc and dry / clean inside . switch back on.
Mine started to work and its been fine since .
ps. mine is a frost free freezer version.
ok!
whizzer, January 2005