loopback won't enable automatically

[Pollywog]

I have to manually set the loopback interface after each reboot on one machine 
(it is a laptop):

ifconfig lo0 127.0.0.1 netmask 255.0.0.0

Then everything is fine.

I added ifconfig_lo0="127.0.0.1 netmask 255.0.0.0"  to /etc/rc.conf
but for unknown reasons it now looks like this and I still need to set lo0 
manually after reboots:

ifconfig_lo0="inet 127.0.0.1 netmask 255.0.0.0"


Any ideas?  I am running FreeBSD 7