It worked fine for me just now. Key thing is that you need to first initiate a download of a Creative Suite 6 product before you can scroll down and select the link to download Master Collection CS5.
You are welcome to contact our support team although we no longer have replacement media available for Creative Suite 5. You can find the support options relevant for your country/region by going to http://www.adobe.com/. Once there click on Help and then Contact Us.
