We were working on a case in which users were unable to mount NFS share from a UNIX machine on a Windows 2003 NFS Client. The NFS share was configured on Solaris and we were able to see the share using the showmount command. usually network error 67 means that the directory is not shared, or the server is unable to resolve the client name. But in our case, we were able to mount the share on different servers and we were also able to ping the NFS server. We update the NFS drivers but that didn't help. Finally we look at the "Provider order" and found that NFS was at the bottom. We change the sequence and bring NFS at the top. This resolves the issue.
Sometimes we need to change the network provider order so that a specific redirector has better preference to be picked up. The Provider Order tab lists the network providers for your computer. You can use the arrow buttons to change the order in which these providers are accessed. You can also arrange the order in which the computer accesses information about the network. Providers and other connections are accessed in the order providers and the connections are listed. Alternatively, you can change the network provider order in the registry. The registry entry is
More details can be found in:http://www.microsoft.com/mspress/books/sampchap/3211b.aspx
Below is the technet article which shows the steps to modify provider order: