I personally haven't heard of any problems with the ailerons fluttering. Not from just flying the plane. Have you eliminated any chance that it could be something with the servos or linkage?
As far as the tail breaking off, I have heard of that happening but it's been a while. Most of the guys now put tail wires on to make sure that doesn't happen. Also it's been discussed that maybe in some instances that on assembly of the tail and cutting off the monocote that people would cut too deep into the balsa and weaken the wood. I don't have tail wires on my 46 and have flown it for months with no problems at all