squeaky belt on '01 Suburban

I bought a 2001 Suburban in August 2005 with 56K miles on it. Shortly after I got it, the belt started squeaking. Since then, I've had it replaced three times. It's good for 100 miles or so, then it starts the squeaking again. This last time I had the pulley/tensioner replaced, too, yet the problem started again. Is there is any other possible cause for this?

There are two belt for your burban I had this problem and used the shorter belt. How is you tension, mine was at the end with the longer belt and perfect with the belt alittle shorter