You're forgetting to add the vocation through sources, should be inside creatures_definitions.hpp
enum Vocation_t : uint16_t {
VOCATION_NONE = 0,
VOCATION_SORCERER = 1,
VOCATION_DRUID = 2,
VOCATION_PALADIN = 3,
VOCATION_KNIGHT = 4,
VOCATION_MASTER_SORCERER = 5...