Just to clarify what I stated earlier, please note that you CANNOT continue to prosecute the state court small claims case against the Debtor in state court unless you obtain an Order Granting Relief from the Automatic Stay from the Bankruptcy Court or the Bankruptcy case is dismissed. At this point, you're not registering as a creditor in state court; you'd be registering as a creditor in Federal Bankruptcy Court.
When a Debtor files for Bankruptcy, something called the Automatic Stay goes into effect. This means that all pending legal actions and collection efforts against the Debtor must stop immediately.
Thus, when you tried to continue your small claims case in state court after the Debtor filed his or her Bankruptcy, the state court judge told you that you needed to "file papers" in order for this case to continue, as the Automatic Stay had gone into effect, meaning that the state court case cannot proceed until you obtain Relief from Stay (via a rather involved process in the Bankruptcy Court - you would need to hire an attorney to do this for you) or the Bankruptcy is dismissed.
In a Chapter 13, most creditors are limited to filing a Proof of Claim in the Bankruptcy case (recovering pennies on the dollar) unless they have a either a secured claim via a valid lien on Debtor's property, a priority claim against the Debtor (typically for child support, alimony, and/or unpaid wages), or the Debtor's case is dismissed. I would strongly advise that you consult with an attorney regarding your specific factual situation to determine the most appropriate course of action for you to take.