While downloading the xls file from server I'm getting an error Sys.WebForms.PageRequestManagerParserErrorException

When I'm downloading the xls file from server, I'm getting the following error: 

Sys.WebForms.PageRequestManagerParserErrorException: The message received from the server could not be parsed. Common causes for this error are when the response is modified by calls to Response.Write(), response filters, HttpModules, or server trace is enabled.

I have took link button and place inside an update panel. when click on link the above error is throwing. How to resolve above error.

 
...