MVC 3.0 Missing Compiler Required Error

I have a MVC 3.0 .Net 4.0 Razor application that is periodically giving me this runtime error:

CS0656: Missing compiler required member 'Microsoft.CSharp.RuntimeBinder.Binder.InvokeMember'

I can temporarily fix the error by deleting this dlls from the bin directory -Microsoft.Scripting.Core.dll -Microsoft.Scripting.ExtensionAttribute.dll

These are re-added when I re-compile and at random intervals I get this error. These Scripting dlls seem to exist because I reference the Facebook dll and also another project which references a .Net 3.5 project. Should these dlls exist in the bin directory of 4.0 project at all?

By the way, I've not upgraded the project from a previous version of .Net and I'm not using Mono as other people have reported.

Im thinking of开发者_StackOverflow just starting a blank new project and copying my stuff into it, but that still could have the issue if I need to re-add the same references. Does anyone else have a better idea?

Thanks!

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This was due to using an older version of the Facebook.dll in my case so maybe look into this if you receive this error when referencing facebook.