I am also receiving the error that to the question:

Is the .htaccess file writeable?

The file is currently owned by 'root'. There is no user-group that contains both the web-server user and the owner of this file. Change the ownership of the file, create a new group, or temporarily make the file writeable by everyone during the install process.

I am using BlueHost as my server, installed SilverStripe in a sub-folder inside public_html. I accessed the properties already and made it public writable for the .htaccess file. Any thoughts why it still is giving that error? Any help would be greatly appreciated! Thanks in advance!