Source: NCP Engine
Explanation: The NCP engine could not perform the file operation; read-only permission was set on the volume where the file or directory exists.
Action: If users are trustees with the Read right and File Scan right, the users do not have permission to modify the files or directories, but they can browse and view them. For users that need to make changes to files or directories, you can make them trustees and grant them the additional rights to Write, Create, Modify, and Erase in the target location.