This forum is only for reproducible bugs with csf and lfd (i.e. not iptables problems, lack of understanding how to use a feature, etc). Posts must be accompanied with full technical details of the problem and how it can be recreated. Any posts not adhering to this, or not considered bugs, will be moved to the General Discussion (csf) forum.
This indicates that iptables has been flushed. I would suspect that you are running TESTING mode, or some other cron job is flushing iptables chains, which will cause this problem while it is trying to insert a rule into a chain.
Sorry this isn't the case. This is happening on our new Centos 5.2 installs .. I've verified that TESTING = "0" .. and there are no crons installed. This is happening on multiple machines. I'm a longtime csf user and never experienced this problem before.
I just tried your configuration on a CentOS v5.2 and didn't have any problems. If you're using a stock CentOS kernel (i.e. not a custom kernel) and can give me access to the server to investigate, please log a ticket on our helpdesk.