From brief research on the matter, Pokemon Channel Jirachi should be fine, too.
Is there another pokemon in your party that could be causing the error? What happens if you catch a magikarp or something generic in Black 2, then only have that and Jirachi in your party?
Is there another pokemon in your party that could be causing the error? What happens if you catch a magikarp or something generic in Black 2, then only have that and Jirachi in your party?