Hi,
If you were adding SNAP as a new theme on your site, which theme we're you using as the default. It cannot have been SNAP if that was a new install, so the problem must be with the Default theme NOT Snap!
On the other hand why did you use FTP when you could have installed the SNAP theme using...
Site Administration > Plugins > Install plugin
That way if there was some incompatibility issues it would have aborted the installation process.
Hope this helps?
Mary