479540 PHP. Need help with simple dynamic url script

I have a script that loads different variables into a page based on the url (example: [login to view URL]) If a user goes to that exact url, different variables loads into the page. However, here is the problem. If the user just goes to [login to view URL] and NOT through a dynamic URL, the variables dont show up. Nothing shows up in their place. The script needs to be built so if a visitor comes through a domain with NO unique ID, it should show default variables instead of nothing. This is a simple script, only 2 pages, and a few lines of PHP code. It also has one database which includes 1 small table of data. I also need some help the PHP form that creates the unique ID, I need an email address form field added, and the ability for visitors to have the script email them their own unique URL if they provide an email address. This project should only take 30 minutes - 1hr at most for a skilled PHP programmer. You must start right away and I will pay when job is done. Please bid if you can start right away.