The Never Ending Story 2 has a different cast from what would include Jack Black. Jack Black is typically associated with his own brand of comedic acting in other projects, not this sequel. His acting style and the overall tone of his work don't really match what The Never Ending Story 2 was aiming for in terms of casting.
Well, since Pokemon White and Black are set in the Unova region where you explore, catch Pokemon, and battle gym leaders. But 'Bowser's inside story' is from the Mario world which is completely different. If this is some sort of crossover idea, it could potentially be about Bowser getting involved in the Pokemon world of White and Black. Maybe he's there to cause chaos or has some strange new adventure that mixes the gameplay mechanics of both universes. But without more context, it's hard to say exactly.
There are so many possibilities for the 'Bernie Jack Black story'. It could be a story from a local community where Bernie and Jack Black interacted in some way. Maybe it's a story related to a project they worked on, or it could even be a story that started as a joke among friends and then spread. Without more details, it's really difficult to give a definite account.