I have published a new beta versiont that will get rich of the Object.prototype.extend that is in conflict with several third-party libraries. Download the beta at http://schwarz-interactive.de/download/6.4.5.2-beta.zip [1] and if you have any feedback please use the thread in the Google group here [2].
The prototype method Object.prototype.extend has been removed to get third-party JavaScript libraries work with Ajax.NET Professional. If you you are using the JavaScript method to extend your objects use following configuration in web.config:
<ajaxNet> <ajaxSettings> <oldStyle> <objectExtendPrototype/> </oldStyle> </ajaxSettings> </ajaxNet>