Since I don`t see any errors in our tests, I could not give you a suggestion how to solve that issue. We are using standard default settings for the browser. Can you try to test the page with IE8 on another machine? Also note that if the error message does not exist in IE9, Firefox and Safari, then it is browser related and most probably it should be fixed by IE (after an update), but I could only suppose what the reason for this error could be.
the Telerik team
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