I just saw this message on our internal bug reporting listserv and I wanted to share. The user was having trouble opening a notebook on SharePoint, the user was getting an error saying “OneNote cannot open the specified location”.
The reason for the error was because the WebClient service is not enabled; which OneNote needs enabled for file-locks. Vista Server 2008 does not have this service enabled by default and if you are running Windows Server 2008 (2k8) you might have this problem. To enable the service, go to Control Panel => Administrative tools => Services => WebClient and click Start (and probably make it automatic).