You won't get a valuation on any coin on-line..simple, first you have to know what it is, how many examples they are, and then you have to send it to, or take it to a potential buyer, preferably to a collector of that type of coin you are selling. I often see on here people refering to book values, book values are just a guide, the price is what someone is willing to pay.
PS..The chances are it won't be a error, but a forgery.
SS