This started happening for me when I upgraded my Mac to Yosemite. I found that Yosemite changed my computer host name and I needed to update my /etc/hosts file with my new name. Add a line for 127.0.0.1 with the new name.

As can be seen in the attached screenshot, when I go to the asset share page, select an item and click download, I am prompted to download a zip file. I download it and when I try to unzip this zip file, receive an error popup that says "Unable to expand %FILENAME% to %LOCATION%".Any ideas as to why...