It sounds like you have the Visual Studio add-in installed and have Visual Studio running when you try to update. I'd recommend you uninstall the add-in before updating anyway or you'll get an error message next time you start Visual Studio.
To successfully update, I'd recommend the following steps:
- Close all Visual Studio instances, and any Reflector instances you have running.
- Start up .NET Reflector 6.7
- Click the Tools > Integration Options menu item, and uninstall the add-in from any versions of Visual Studio you have installed.
- Now click Help > Check for Updates
You should then be able to successfully go through the update process.
If you run into any more problems, please give me a shout.