I updated my AJAX Control ToolKit, to the latest version, and now I'm getting this error:  Parser Error Message: Unknown server tag 'asp:ToolkitScriptManager'.

I didn't change any code, just replaced the .dll in the bin.  Is there something else I need to do?  So frustrating....

I already have this on my page  

<%@ Register TagPrefix="asp" Namespace="AjaxControlToolkit" Assembly="AjaxControlToolkit" %>