We do not offer official support for integrating Telerik.Web.UI.dll v2010.1.309.20 in SharePoint 2010. We provided webparts installer in Q2 2010, version 2010_2_713 (RadControls_for_ASP.NET_AJAX_and_SharePoint_2010_Dev.msi).
My personal suggestion is to download the latest Q1 2012 SP1 built of Telerik_AJAX_Controls_For_Sharepoint2010_2012_1_411_Dev(or Trial), which was released yesterday. It offers support for all modern browsers, multiple bug fixes and many new features. You can find installation instructions in the following article: Installing RadEditor & RadGrid Web Parts on SharePoint 2010
the Telerik team
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