If a home has an abstract of judgement, can the owner sell the property?

First, ignore the term "abstract." This means you have a judgment against you...at some point someone sued you. In North Carolina, judgments are automatically a lien on real property that you own. The real estate agent is correct. The Mortgage company will not agree to a short sale because they will take the home with the judgment, making it less marketable. If you don't believe you were ever sued, you need to check the Court records and see who obtained the judgment against you.