Here is where your problem probably is.........
When you made the transaction with the original owner did you have a title company involved?
Just because you hired a surveyor and sectioned off the tract of land titled in your name does not mean there was not an claim by a creditor existing.
That is why a Title company would be a necessity in real estate transactions.
Very well could be a legitimate claim that was not uncovered due to the small amount of money saved by not involving a Title company.