In certain ASP.Net Ajax callbacks, and only on some servers, I am getting the error
Error: Unable to get value of the property 'async': object is null or undefined
It appears to me that this is the multiple callback error that was supposed to be fixed in .Net 3.5 SP1 according to Microsoft, and this is born out by examining the versions of WebForm_CallbackComplete that are generated on the failing servers. This implies that SP1 is not being used by the site, but it is installed on the server. How would I verify whether SP1 is being used by the web site, and what needs to be done to upgrade it if it isn't being used?
Thanks!