[Emp`]

change 139-158 to

public Shaman_damage(id)
{
	if (!shModActive() || !is_user_alive(id)) return PLUGIN_CONTINUE

	new weapon, bodypart, attacker = get_user_attacker(id,weapon,bodypart)

	if ( is_user_alive(attacker) && id != attacker && gIsZombie[id] ) {
		if ( bodypart==HIT_HEAD && weapon!=CSW_HEGRENADE ) {
			shExtraDamage( id, attacker, 500, "Headshot" )
			client_print(id, print_center, "Your undead head has been blown off.")
			client_print(attacker, print_chat, "[SH] You killed an undead with a headshot.")
		}
		if ( weapon==CSW_HEGRENADE ) {
			shExtraDamage( id, attacker, 500, "Blown Up" )
			client_print(id, print_center, "Your undead body has been teared apart by a grenade.")
			client_print(attacker, print_chat, "[SH] You killed an undead with a grenade.")
		}
	}
	return PLUGIN_CONTINUE
}

tell me your results again...