I have umbraco 4.7.1.1 installed with a few additional modules, including Contour and uWebshop. We have also at various times installed (and then uninstalled) Darren Ferguson's workflow project, uBlogsy and Courier.

I have searched the above error and foudn various posts relating to it (this one for example: http://our.umbraco.org/forum/developers/razor/22220-Extension-Methods-not-working) , which seem to imply that it could be either the presence of specific DLLs (e.g. Microsoft.Scripting) or that one of the core files might have been overwritten by the installation of a module.

This is causing a lot of extra work because you need to work around it the whole time.

For example the standard Inline macro for pagination that ships with Umbraco does not work at this bit:

@foreach(var item in pagesToList.Skip(currentPage*itemsPerPage).Take(itemsPerPage))

where 

var pagesToList = @Model.Children;

Has anyone been able to pin point yet exactly which DLL is the cause? If so does anyone know what version of the DLL to replace with and where can I get it from?

Any ideas would be gratefully recieved!