When you boot off the network, are you using the same /etc/modules.conf file? You should be...
Also, when you boot off the network, are you using the same init scripts (is everything in /etc/rc.d/init.d the same)? Are you passing the same options on the kernel command line from your bootloader? (I'm actually not quite sure how "booting off the network" works, but I would assume there's a way to pass options to your kernel, right?)