Could not load file or assembly "Microsoft.Web.Extensions"

As it turns out, I had been given an incorrect web.config by the previous developers. Putting the new one in allowed me to compile and build the solution.

Once deployed to the server, I had installed the AJAX for ASP.NET 2.0, but still received errors referencing microsoft.web.extensions etc.

The solution lie in the versioning.

The whole application seems to be built on top of the AJAX for ASP.NET Beta 2 binary. After removing the 2.0 and re-installing the beta 2 MSI, everything fired into action.

Thanks for the pointers everyone.

You should install on your server the ASP.NET AJAX for Asp.Net 2.0. You can find it here: http://www.microsoft.com/download/en/details.aspx?id=883

If you don't have access in this server, you can upload the .dll file into the bin folder.

I hope it works!