Add-on for existing script

I need an add-on for a current script. The current script is in cgi and does not need to be changed. What I would like is a [login to view URL] file (this will be the "thankyou" page for customers) that uses paypal_ipn for payment processing. The [login to view URL] file should display an [login to view URL] file upon successful payment. Access to [login to view URL], [login to view URL], and [login to view URL] should be restricted allowing only those who have passed successfully through the paypal_ipn file to have access. Unsuccessful payments or attempts at unauthrized access to the above files should be sent to the h_error file. The current script I have has files that perform a similar function. The [login to view URL] file is currently set up to display the [login to view URL] file and unauthorized access is directed to the h_error file. I've left this just as an example in case the programmer need to view it. I've attached the entire current script in a zip file for review. There is also a !!-READ ME-!! file inside the zip file that shows working links for the current configuration of the script. ## Deliverables 1) Complete and fully-functional working program(s) in executable form as well as complete source code of all work done. 2) Deliverables must be in ready-to-run condition, as follows (depending on the nature of the deliverables): a) For web sites or other server-side deliverables intended to only ever exist in one place in the Buyer's environment--Deliverables must be installed by the Seller in ready-to-run condition in the Buyer's environment. b) For all others including desktop software or software the buyer intends to distribute: A software installation package that will install the software in ready-to-run condition on the platform(s) specified in this bid request. 3) All deliverables will be considered "work made for hire" under U.S. Copyright law. Buyer will receive exclusive and complete copyrights to all work purchased. (No GPL, GNU, 3rd party components, etc. unless all copyright ramifications are explained AND AGREED TO by the buyer on the site per the coder's Seller Legal Agreement). ## Platform Server side script that should run in all 6.0+ versions of Internet Explorer and 2.0+ versions of Firefox