Hello,
I just tried installing it and it worked fine for me and I was able to complete the install. The only thing I can think of is trying to update it via a Joomla patch, perhaps some php files aren't compatible with your server version. The Site Shaper is Joomla version 3.3.6. So you could extract it again and then grab an update file here:
"Update from Joomla! 2.5, 3.0, 3.1, 3.2 or 3.3":
https://github.com/joomla/joomla-cms/releases/tag/3.4.8