GCHandle routines fail: AddrOfPinnedObject() and FromIntPtr()

Why does the following code crash the executable (I launch from the VS debugger):

    static int Main(string[] args)
    {
        byte[] hash = new byte[20];
        GCHandle gch = GCHandle.Alloc(hash, GCHandleType.Pinned);
        IntPtr MyPtr = gch.AddrOfPinnedObject();
        GCHandle temp = GCHandle.FromIntPtr(MyPtr);  //This line crashes the executable (the exception cannot be caught!!!!).
        temp.Free();

        return 0;
    }

The system event log says:

     .NET Runtime version 2.0.50727.3053 - Fatal Execution Engine Error (000007FEF95CAA6E) (80131506)

I am running on Vista x64 SP1 with VS2008 SP1 with .net 3.5 SP1.  I have found a thread of discussion where somebody says its a .net bug for which MS provided a February 2009 hotfix:

   http://stackoverflow.com/questions/334706/fatal-execution-engine-error-79ffee24-80131506 

But when I look up the the listed hotfix ( https://connect.microsoft.com/VisualStudio/Downloads/DownloadDetails.aspx?DownloadID=16827&wa=wsignin1.0) it doesn't say it has any relationship to the problem I'm facing (nor does it say which files I need or how to install them).

Have I found a new .net bug?