AJax and Server 2008 R2 - Failure to load Assembly

New to Ajax. Developed web application on Wndows 7 Pro using VS 2010 and the 4.0 framework. Using Ajax and the tab controls. Works fantastic on the development system
Send it over to the Windows 2008 Server R2 and getting the attached error. Could not load assembly 'AjaxControlToolkit' .... (see rest of the attached error please)

Can anyone point to/give a resolution for this? Thanks

gollnick

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