QV Desktop uses the IE engine to emulate the AJAX session. Which IE version are u using? I experienced a problem with one extension (SVG Map) which was incompatible with IE10. But after a while a new version of the extension was released with the fix.
Also, I found this info in the SR2 release notes: "On systems using UAC (Windows user access control), WebView may require that QlikView is started using the “Run as Administrator” option.". Mine is set to "Never notifiy" and I don't have to "Run as Administrator".