The problem is caused by the fact that there are two jQuery instances on the page. The second one is registered by the RadScriptManager and it overwrites the first one. As a result, the jQuery plugin definitions are lost (the Kendo widgets are in fact jQuery plugins).
The Kendo scripts should be registered on the page after the jQuery file. The RadScriptManager renders its <script> tags at the end of the <head>, so you need to place the Kendo scripts in the <body>.
You should also keep in mind that the jQuery registered by the RadScriptManager may be older and not compatible with Kendo UI, that currently works with jQuery 1.7.1. In this case you can register a custom jQuery via the RadScriptManager:
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