Since Q3 2011
all the built-in skins are located in the Telerik.Web.UI.Skins.dll
assembly, so you need it as well. More information is available in this help article
. The change was announced in a blog post with Q2 2011 (here
) and again with Q3 2011 (here
Please, go to the bin folder and make sure that the Telerik.Web.UI.Skins.dll assembly exists in it.
the Telerik team
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