hmm weird one.was there no earth in the main fuse box?cant believe a house was wired up without using an earth.you shouldnt be gettin a shock just cause there is no earth.there is still definetly problem as if you are gettin voltage to earth it would lift a fuse.one thing to check if you have some test lamps on you is check between neutral and earth as a lot of folk dont know if a neutral becomes slack somewhere or gets split then it becomes live aswell.had this problem many a time.