I have installed the plugin and activated it (without changing any of the configuration settings) and get an error when accessing the site:
You don't have permission to access /wp-content/w3tc/pgcache//_default_.html.gzip on this server.
Apache/2.2.3 (CentOS) Server at http://www.news.cyprus-property-buyers.com Port 80
Permissions set as follows:
wp - 755 (folder containing WordPress)
wp-content - 755
w3tc - 755
pgcache - 755
_default_.html.gzip - 600
I have set the page cache to 'Disk (enhanced)' and 'Disk (basic)', and disabled everything else, but the problem persists.