I ran a new phone line and connected it to the protector. It has a terrible hum on the line. The other lines connected to the protector are fine. I've re-run with new inside wire and get the same result. It's not the phone; I also get the hum on the butt set. What can I do to eliminate this noise?

Disconnect wires on the 2 terminals, test, If any wires are left connected, is a potential cause of the hum. If hum still there. It is Phone company responsibility to the box. Have not seen them charge to that point(D Marc), they may come out and unscrew defective protector, and replace.
Have to say again, ALL wires, MUST be removed from the 2 terminals to determine inside
Or outside problem.