When you attempt to run NBTSTAT and reference a remote computer, like nbtstat -a RemoteComputer, you receive:

Failed to access NetBT Driver - NetBT may not be loaded.

If you are NOT a local administrator, this issue will occur.

To workaround this issue, either log on with administrative privileges, or use Run As.

NOTE: Also see How can I configure the Run As (SecLogon) service on my Windows 2000 and greater clients?