Port conflict with other service?

My friend tried to join my cracked Hamachi server today but it said Connection Timed Out: Connect. So I told him to open the port 25565 but it said "Port conflict with other service." He is using the modem Netgear WGT624. Can someone help me? Thanks

Why should he portforward if a) you are hosting the server and b) you are both using hamachi?

he must only join your hamachi network and write the correct ip, no need of portforwarding