Guys, Im getting this strange error when somebody makes an account on my zen cart. It results in no shipping or billing address!

HTML Code:
[11-Dec-2012 13:41:14] PHP Fatal error:  1062:Duplicate entry '613' for key 'PRIMARY' :: insert into customers_info

                          (customers_info_id, customers_info_number_of_logons,

                           customers_info_date_account_created, customers_info_date_of_last_logon)

              values ('613', '1', now(), now()) in website.com/includes/classes/db/mysql/query_factory.php on line 120
I dont think it is the query file is it? What would this mean?

Many thanks!!!