did you install the dish yourself?
if so, call bell and tell them you moved, to your new home, and want your system set up (they will send a tech for the "free move" promo
it could be a bad sw21 switch, LNB, or just not aimed right
when you run the check switch, does it recognize the sw21?
if so, then it is most likely an aiming issue
if you aimed it yourself, did you make sure the mast/arm was level on the front and side?
if not, then aiming will be very difficult
if it was level, then you shouldnt have had to change the elevation/skew
good luck
btw on the topic of going on roofs
you have to think of the bad weather
if you put the dish on the chiminey in the summer, remember, if an LNB fails in january, you will be hard pressed to find a tech willing to risk his life, for a few bucks by climbing on an icy roof
rest assured the CSR will tell you the tech can do it no problem (they are great at gambling when it is someone elses safety/life at stake) but most techs will/should refuse working in unsafe environments, even though they are pressured to do so for something as trivial as tv........