Most likely the upload and download behaviors are using the same trigger.
You will need to use a unique trigger for the upload and the download behavior in order for them to work on the same page.
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.