Assembly daypilot.dll uses 'System.Web.Mvc, Version=4.0.0.1, Culture=neutral, PublicKeyToken=31bf3856ad364e35' which has a higher version than referenced assembly 'System.Web.Mvc, Version=3.0.0.0, Culture=neutral, PublicKeyToken=31bf3856ad364e35'
Both DayPilot Lite and DayPilot Pro for ASP.NET MVC downloads include binaries for MVC3, MVC4 and MVC5 (see the Binary folder in the .zip package). It looks like you are trying to use the MVC 4 binary with ASP.NET MVC 3.
No i was used for mvc3 only