During the installation, I received a warning stating that it could not open the stream 'wp-content\plugins\wordpress-bootstrap-css\Less.php'. It allowed me to activate the plugin anyway so I did and I could not get Bootstrap activated.
As for the first problem, I found that Less.php is actually a folder and not a file. Is that a bug?
For the second problem, I'm aware that the default style.css is linked but is the plugin suppose to work out the box after configuring the settings, or do we suppose to change the stylesheet link in the head tag? If the latter, what do we change it to? I did not see a css folder or the file anywhere for Bootstrap. Is this a consequence of the first warning I mentioned above?