Some people have reported problems downloading releases from the Workspaces application; either they find a 0 byte file, or are presented with the message 'The Compressed (zipped) Folder is invalid or corrupted'. Either way, not fun.

From the list of late-breaking issues:
On downloading a release, the error message "The Compressed (zipped) Folder is invalid or corrupted." is shown
This corresponds to a known problem in the way Internet Explorer downloads compressed files. For more information, see KB 308090. As suggested in that article, this problem can be worked around by first saving the compressed folder to disk, and opening the release from the saved location.

So, the KB has background and the workaround is to save to disk. What if you never have that option? You may have (inadvertantly) configured your machine to always open ZIP files, without asking you first. To fix this, open up any Windows Explorer window, Tools/Folder Options, then on the File Types tab find ZIP files and click Advanced. Finally, make sure the 'Confirm open after download' box is checked.

All fixed.