I'm a bit late with an answer, but maybe will help someone...

I had the same problem on Vista, because I installed MM without turning off UAC (I read the instructions only when I get some errors :) )...

So the easyest way to solve this is to uninstall MM... turn off UAC... restart the computer... install MM... then you can turn UAC on, and it will work perfectly...

There is a second way but it's more complicated, you have to change access permissions for:

- folder C:\Program Files\Microsoft Visual Studio 9.0\Common7\IDE - here will mmBLG.config be created

- registry key HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\VisualStudio\9.0\Projects\{FAE04EC0-301F-11d3-BF4B-00C04F79EFBC} - the generator read this key

maurizio