Converted .net framework 3.5 to 4.0 now i get a scripting error whenever i try to do a postback

Question

The action is being fired from a button inside an update panel. I have triggers on the button as well.

This is the Error:

Sys.WebForms.PageRequestManagerServerErrorException: Object reference not set to an instance of an object

When i view the trace this is the function it is failing on:

function Sys$WebForms$PageRequestManager$_endPostBack

Answer 1

A general idea:

Where do you call it from ? Local IIS or VS Devserver ?

If iss, check if the AppPool of the Site points already to 4.0.

Cheers Sascha