Ajax (The system cannot find the file specified) IIS Server webpage

I dont know what I'm doing wrong, anybody help?.
 
I have put the Ajax toolkit folder on the IIS Server in our web pages folder. The folder contains the sample websites and the controltoolkit.dll file etc

 
then in visual studio I have opened one of my websites that is located on the IIS server and I have added the ajaxcontroltoolkit.dll file to the website by browsing for the ajax controltoolkit.dll that is located on the IIS server. But when I go to run my website I get the following error:
Could not load file or assembly 'AjaxControlToolkit' or one of its dependencies. The system cannot find the file specified.
 If i do it locally on my pc it works, just doesn't want to work when running websites from the IIS server.
 

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