Your best bet is to talk with a lawyer, familiar with the laws in that area where you signed the document, who would know exactly what the contract intended. You may find that the contract was poorly constructed and you can have it interpreted your way.
Even if it has an error is one part, there may be other data that clarifies and gives a specific meaning for the language used. If it is clear from other wording what the intent was meant to be, you may be out of getting this resolved in you favor.
See a lawyer.
I am not one, but my third cousin's sister is married to a someone who knows one.