well, Congrats on getting this far... the battle is over, now the fun begins!
This is telling you that the kernel has a problem w/ your network card (as you said). You are going to re-compile your kernel and either build the driver into the kernel, or as a module. What card do you have, or better yet, do you know the module that you are using in slack? (you might be able to check out /etc/modules.conf and get it)
make menuconfig #This is where you can configure it all
2) no, LFS doesn't have the rc.modules. If you have looked at the rc.d tree, you'll notice that all of the bootup files are in /etc/rc.d/init.d and they are linked to from /etc/rc.d/rc[0-6].d.
If you want to add some modules, you are going to need to edit the existing scripts, or write your own (from scratch, remember
. I would suggeest just compiling a lot of stuff into the kernel at first so you don't have to deal with modules that much. After that, you can read up on using modules and then play around with them.
3) it's 'useradd', you had it backwards... I always thought it should be your way too though ;-)
4) You can definitly delete it, or you can tar & bzip2 it up so that you can use it later (if you REALLY fsck up your system) so that you don't have to go through that whole first step again.
Well, have fun!
I just checked out the adduser program that is on my slack box, it's just a shell script. You can probably copy it over to your LFS partition and use it just fine.