HELP!! Roof leaking!?

I have a metal corrogated roof on my cabin and everytime it rains it leakes where it is joined together. I have tried some of that tar roof repair,a sealing tape with some kind of tarry stuff on the back and they seem to work for a little while until the house settles and I get leakage again. Anyone know of any silicone or other flexible type sealer that I can try to fix this problem??? Any suggestions would be greatly appreciated!!!