Just ran into this problem as well. Took a while to figure out why network packets were not forwarded even though "net.ipv4.ip_forward = 1" was set in /etc/sysctl.conf.
- Bug#732920: procps: sysctl --system fails to load /etc/sysctl... Pete Wyckoff
- Bug#732920: procps: sysctl --system fails to load /etc/s... Craig Small
- Bug#732920: procps: sysctl --system fails to load /etc/s... Allen Chan