silverlight webbrowser control InvokeScript error

I am running OOB silverlight ap开发者_JS百科plication where I have a WebBrowser control but I am getting this error when I call InvokeScript:-

Attempted to perform an unauthorized operation.

Is it because it's OOB ?

No it can't be because its OOB since WebBrowser only works OOB anyway. I can think of two possible reasons.

• The Url to which the WebBrowser has navigated is not on the same site from with the Silverlight application has been loaded. This would a security violation.

• The code that is being executed in the loaded web page by the InvokeScript is the actual source of the error.