If you get an error:
Sys.WebForms.PageRequestManagerServerErrorException: An unknown error occurred while processing the request on the server. The status code returned from the server was: 0
just add this code in HEAD section of your page/masterpage:
<script language="javascript" type="text/javascript">
Sys.WebForms.PageRequestManager.getInstance().add_endRequest(endRequest);
function endRequest(sender, args)
{
// Check to see if there's an error on this request.
if (args.get_error() != undefined)
{
//$get('Error').style.visibility = "visible";
// Let the framework know that the error is handled,
// so it doesn't throw the JavaScript alert.
args.set_errorHandled(true);
}
}
</script>
