Pokemon Bank doesn't work with Black 2, only with ORAS and X&Y
If you mean PokeTransporter, then there isn't much you can do, PT is known to let some hacked Pokemon through, whilst not letting other legit ones through, this usually occurs with shinies or signature moves like Night Daze.
There are a few things you can try;
1) Make it forget Night Daze
2) Reset the EVs with berries.
3) Make sure it isn't holding anything
It may be one of these that's getting caught by the PT checker, if this doesn't work, then I'm afraid you're stuck.