This is due to failure to connect to the remote share or registery on the target during scanning. This is often due to rights not existing to target machine, or services being disabled such as file sharing.
The remote registry service on the target needs to be enabled. Simple file sharing must be off. Workstation/server services need to be running. Ensure you can connect to the remote registry under registry editor on the console machine> file> connect to network registry and browse the targets registry.