I dont know what that error means, but default webserver and TCP stack options may not be helping. I investigated a Centos box with resources issues a while back. It had many thousands of sockets in TIME_WAIT state.
IIRC i reduced /proc/sys/net/ipv4/tcp_fin_timeout from 60 to 15, and enabled pipelining on the webserver, along with a few other webserver tweaks. First quick check if it happens again: netstat -an | grep -ci wait If it returns a five figure number then the above would be worth a look.
