Do you have php safe mode turned on?
Are you able to telnet into your host, go to /home/overgami/public_html/wp-content/plugins/w3-total-cache/lib/W3/ConfigKeys.php and view it?
Command:
less /home/overgami/public_html/wp-content/plugins/w3-total-cache/lib/W3/ConfigKeys.php
If it shows nothing or an access denied error then there's some wrong read / write attributes or server settings.
Also, setting directories to 777 not only exposes you to massive security risks but it is also completely useless (and not working) at file level.
I.e. if you uploaded W3TC files with a certain FTP user that is not the web server's, but files are marked as 644 or 600 then you WILL incur in obscure issues.