crashdump debugging with Visual Studio 2010

I am trying to get crash dump debugging working with 2010, but it keeps failing.

I get this error when I try to start debugging:

"Managed Minidump Debugging: The signature verification for the file 'C:\Windows\Microsoft.NET\Framework\v4.0.30319\mscordbi.dll' failed with the error 0x800700c1.:

I'm using the simplest program I can think of just to get off the ground (below).

Here are the steps I am taking:

1. Build
2. Run with a double-click from Windows explorer
3. right-click on the process in TaskManager, and select "Create Dump File"
4. kill the process
5. open the dump file in Visual Studio (File | Open, set filter to crash dumps)
6. Select "Debug with Mixed"

much loading of symbols (I have MS Symbol server enabled)

Boom (I get an error dialog saying I need to specify my symbol path -- which I believe I have done -- MS symbol server is enabled, and my solution is loaded)

In the output window, I get the following error (note that there are also a bunch of successful symbol loads, including for my exe):

Managed Minidump Debugging: The signature verification for the file 'C:\Windows\Microsoft.NET\Framework\v4.0.30319\mscordbi.dll' failed with the error 0x800700c1.

(All the while, the solution with the code for my exe is loaded in the Visual Studio instance).

Any idea what I am doing wrong? Is this the right procedure for crashdump debugging in VS 2010?

The test dummy program:

    class Program
    {
        public static string AStaticProperty = "Hello World";
        static void Main(string[] args)
        {
            DoLoop(10000);
        }

        static void DoLoop(int iterations)
        {
            for (int i = 0; i < iterations; i--)
                System.Threading.Thread.Sleep(500);
        }
    }

Edit

I'm going to vote to close -- I don't know exactly what the deal is, but everything is working now.

Here's what I did:

1. I started debugging the running process in VS 2010
2. I used the "save dump file" option off of the debug menu in 2010
3. I stopped the process and loaded the dump file.

It worked, so I thought "hmm, maybe the problem was with the dump file that I created (had used both adplus and TaskManager).

But no, now those work too. (although they failed very reliably until I did the 3 steps above). Weird, but now I cannot repro, so I'm going to vote to close.

Maybe this question/answers "Symbol issue when debugging C# code" helps you out.