it usually means your boot scripts are trying to initialize the network card but the module is not loaded
you need to know the correct module for your card.
dmesg should list the type of card if it's detected. modprobe can be used to load the module
you should have the following in /etc/modules.conf
module would be replaced with the name of the module
you need to run this
you need to have module support in the kernel before any of this will work
you can also build a kernel that supports the card without a module