Bankruptcy Law Questions? Ask a Bankruptcy Lawyer.
You've got an executory contract, which is basically a contract that has not been fully performed. At this point, the buyer cannot fulfill the contract because he is bankrupt. Thus, you will need to file a motion to have the executory contract cancelled. This will allow you to retake your property and get out of the bankruptcy. This should be a mere formality if the bankrupt is agreeable to doing this.
You need to speak to an attorney about filing this for you.