asp.net and ajax

Question

i've used update panel on my page and when i run the application sometimes not always it shows 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.

on that page

i saw elon's block  http://weblogs.asp.net/leftslipper/archive/2007/02/26/sys-webforms-pagerequestmanagerparsererrorexception-what-it-is-and-how-to-avoid-it.aspx

,i tried everything what he saud but problem is still there.....


any idea !