I think it's telling you that your configuration does not meet the "Linux Standard Base
." (If so, that's a rather cumbersome way of saying "syntax error.")
You don't mention what distro/version you are using, which is useful information because there can differences among how different distros do things. I can
share my static ip configuration from my Debian system.
# The loopback network interface
iface lo inet loopback
# The primary network interface
iface eth0 inet static
# iface eth0 inet dhcp
You might also check your router configuration. Most routers allow you to identify a pool of addresses for DHCP. The last one I installed started DHCP with xxx.xxx.xxx.2 (something I changed immediately). If yours does the same and the address you want to use as static is in that pool, it could be causing some confusion with the static IP.