Protection Stone Unregistered?

[Potassium42]

When placing the protection stone I received for registering earlier I attempted to modify the protection to allow a friend of mine who shares my house to be unaffected by the protection. However, it came up with a message that said "Coal Ore not registered!" and wouldn't do it. I looked through the /lwc and /ps commands but couldn't find anything that seemed to relate to registering a protection stone. What do I need to do?

[Ktayah]

I am having the same problem