6 Instances of same site causes changes to others

I wrote an aspx page in VS2008 and I wanted to open 6 instances of the same page with a different query parameter passed to each.
 
http://myserver/mypage/?myparameter=1
http://myserver/mypage/?myparameter=2
http://myserver/mypage/?myparameter=3
so on.
 
It works fine for one or two at a time, but when I get more than that it starts changing.  So when I try to open the one for parameter 167 it will affect the one for paramter 129.
 
In the page I have a connection to an external sql database.  A gridview control, and an iframe control.
 
Any advice would be greatly appreciated.
 
Thanks,
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