clean all errors with oscommerce

We have oscommerce site that needs all errors solved and errors free. Your task will be: 1. take last oscommerce version and install it on the site 2. use existing template we have 3. find error and fix it on existing questionnerre form we have with site after sign up for account so all questionarre are recorded sucesfully 4. keep 4 payment gateways we have, copy paste them but enable them so every order made is recorded in backend 5. keep the same URLs and existing ones 6. test fully so any errors are solved We will release funds only with errors free site and with requirements solved by you.