duplicate pages problem

[Sergio8]

Hi, everyone!
I have this site http://www.mymovingneeds.com and some time ago I started to get some problems with this page of my site http://www.mymovingneeds.com/find_moving_companies.aspx.
It had PR5 , but now has pr0
If you will do a search like "find_moving_companies.aspx" in google you will see some strange pages in the results , like this one "http://www.mymovingneeds.com/find_moving_companies.aspx?si=sbo&pi=56". this page with parameters are urls we made for tracking the clicks from advertisement campains (for example in superpages.com). But the strange thing is that google now gave a PR to such pages and the original page in site became PR0.
How can it be solved?

wainting for your help
thanks