I've updated to .5 and my website now has severe problems - requests time out or don't return any database content. W3TC is notifying me of the same errors as @alexwoolfson and @MediaInk mentioned:
"It appears Page Cache URL rewriting is not working. If using apache, verify that the server configuration allows .htaccess or if using nginx verify all configuration files are included in the configuration."
It appears Minify URL rewriting is not working. If using apache, verify that the server configuration allows .htaccess or if using nginx verify all configuration files are included in the configuration.
I've re-created all W3TC config & .htaccess options but still not solved.