> $sql = "INSERT INTO $db_table4
> (firstName, lastName, dob, category, address1, address2, city,
> state, zipcode, telephone, cellphone, email1, email2, aimid, url,
> notes)
> VALUES
> ('$firstName', '$lastName', '$dob', '$category', '$address1',
> '$address2', '$city', '$state', '$zipcode', '$telephone',
> '$cellphone', '$email1', '$email2', '$aimid', '$url', '$notes')";

Also just noticed I presume that line is meant to actually read:-

$sql = "INSERT INTO $db_table

you have an eroneous 4 at the end of the table name