I can't imagine any situation where the NBA are trying to shut down your videos! It must be something automatic on youtube that's flagging them. As I said it must be something to do with the particular video.
What network is the footage from? How long is the video?
If the highlights are from a nationally televised game it could be that youtube has recognition to see the network logo and certain network logos are automatically flagged and rejected.
I would try to contact YouTube and see if they can help answer why that particular video was rejected, when all the other ones you've uploaded have gone through fine.