Hello,
Did you download directly from github or download as below? I couldn't get the download from github to work but I was able to get the download below to work.
On this page:
http://www.silverstripe.org/user-forms-module/
Look for latest master build on the right hand side of the page (you need to scroll to find this).
The file is called:
silverstripe-userforms-master-HEAD.tar.gz
Cheers,
Gary