The Microsoft .NET Framework is a programming and run-time environment that runs on Microsoft Windows. Programs written for the .NET Framework execute in a software environment known as the Common Language Runtime (CLR). The CLR is an application virtual machine instead of accessing the hardware directly. A program written for .NET requires that the .NET framework must be installed before the new program can run. ^{source: wikipedia.org}

Many of the 2012 family of products use version 4 of the .NET Framework. As Through the Interface blogger, Kean Walmsley, has pointed out: .NET 4.0 implements slightly more stringent security than prior versions of the framework: if a Dynamically Loadable Library (DLL) is suspected as having been downloaded from the web – as is clearly the case with our technology previews – the .NET 4.0 runtime will treat that DLL as if it has been loaded from a network share. And as many of you have found out, from trying to load DLLs from network shares, this results in a reduced set of privileges on the local machine, which can often result in a load error.