allow for .axd files
- Open IIS management snap-in ( e.g. run inetmgr.exe)
- Right click your website and choose properties
- Go to the "Home Directory" tab and click the "Configuration" button
- A dialog should pop out and you would see the mappings listbox
- Find the entry for the ".axd" extension and edit it by clicking the "Edit" button
In the new dialog uncheck the "Verify if file exist" checkbox - which I suspect is causing the problem.
I had to uncheck "Verify that file exists" for the "Wildcard application map" for SiteMinder (Website Properties->Home Directory tab->Configuration). Once I made the change, my browser started receiving webResource.axd If this does not work for you, create an empty file named 'webresource.axd' and place it in the root of your application. Then the file will exist and it won't matter what the settings are in IIS or SiteMinder.