The rules relating to subpoenas in bankruptcy cases are found in Rule 45 of the Federal Rules of Civil Procedure.
Does the subpoena you received require you to appear and testify or only to produce documents?
A subpoena is not an invitation that you're free to decline. You're under a court order. If you just blow it off, you could end up being arrested or sanctioned.
A letter to the lawyer who issued the subpoena that explains that you have no responsive documents and are not familiar at all with the persons or events involved in the case would be a smart thing.

