Apply the following changes to your database:
ALTER TABLE cust_main CHANGE state state varchar(80) NULL;
ALTER TABLE cust_main_county CHANGE state state varchar(80) NULL;
ALTER TABLE cust_main_county ADD country char(2);
UPDATE cust_main SET country = "US" where country IS NULL OR country = '';
UPDATE cust_main_county SET country = "US" where country IS NULL OR country = "";
CREATE TABLE cust_main_invoice (
destnum int NOT NULL,
custnum int NOT NULL,
dest varchar(80) NOT NULL,
PRIMARY KEY (destnum),
INDEX ( custnum )
);