I also facing the same problem. I had setup a VPS with 4GB RAM and CentOS 6.5 64bits, CWP version 0.9.7 installed. This VPS has the clamav, amavis, antispam, csf firewall, varnish enabled.
Initially everything working fine but few hours ago all the services i.e. web, email, ssh & CWP went down, could not even connect through SSH. I have to connect from the web console provided by vendor to execute the command "service iptables stop" then everything up again. However, I noticed as long as I tried to start the csf firewall the VPS will down again.
For now, I have to leave the csf firewall disabled. Any idea what has causing this problem??