Nostalrius Begins - Quality wow vanilla realm (1.12)

when i try to the quest 'taming the beast' i am not possible to tame my second beast. the first one (boar) works fine. the second one (surf crawler) is not possible. it always says: invalid target, can someone help me pls??

try deleting your WDB folder while the game is closed

Dismiss the Boar before going for the crawler