The most probable reason for that issue is that you hadn't installed Kendo UI. The VSExtensions are for Visual Studio integration only (Telerik menus, project templates, ...).
I recommend you downloading our Control Panel. It gives you the ability to download and manage (install, upgrade, repair, uninstall) most of the Telerik products including Kendo UI.
You can also download the product from the Kendo UI web site.
Here are the links for ease:
Control Panel - http://www.telerik.com/account/default.aspx
Kendo UI - http://www.kendoui.com/account.aspx
Please do not hesitate to contact us for any further assistance.
the Telerik team
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