Perhaps a value is not getting passed like you think it is.
You could try to echo your URL vars on the page to see what happens.
If you post the code, I will also take a look and let you know if I see anything.
Your friends over here at WebAssist! These Dreamweaver extensions will assist you in building unlimited, custom websites.
These out-of-the-box solutions provide you proven, tested applications that can be up and running now. Build a store, a gallery, or a web-based email solution.