How to get out of a data use agreement?
This isn't a question that can be properly answered here as it may have legal implications that are local to the actual case. Don't make assumptions that your old agreement is null, just because the data became public. No harm no foul might not hold up anywhere, especially if lawyers get involved. 

You indicate that the director is a different person than the one who helped you. He/she can give you advice. The legal department of the institution can give you advice that should hold up. If your new work is truly independent of the old, make sure that they understand that. The other person may have no moral hold over you for co-authorship, but only an expert can speak about a legal hold. 

The question is likely too old to be of help to the OP, but future visitors may have similar questions, hence this very late answer.