ASP Remote Scripting Cancel

Hi,
i have a page with a query and cancel button. the page takes more than usual time to load. So on query i shouldn't submit the page but get back the result. (so i used remote scripting to call server methods asynchronously. this works very fine). on the other hand, on click of cancel button, the request should cancel and the page should remain as such without any refresh/change. This also works fine the first time. But if I click query and cancel alterntively, query fails the third time. I'm not able to find what has caused this error.
If I refresh the page on click of cancel, then everything is OK. But I can't afford to refresh the page on each cancel. Help me out please.