I believe the issue here is one of permissions. I know you stated you have the necessary permissions, but that doesn't mean your application does. First, if you are running on Windows 7, you will need to make sure you are running your app as administrator (the mode, not just logged in as admin).
Next, you might need to look at impersonation. It looks like this Stack Overflow question describes a similar issue and it has a listed solution:
Here is another one with code listed: