Hi,
I've experimented on several different systems, all with the same result.
The 2.2.14-12 kernel, if used when installing for the first time, will
not load the appropriate network modules.  It complains about unresolved
symbols.  For example, on an ne.o module complains:
unresolved symbol ei_open
unresolved symbol ethdev_init
unresolved symbol ei_interrupt
unresolved symbol NS8390_init
unresolved symbol ei_close

This happens with several other modules (i've tried this also using a
intel etherpro 100).

The module is found on the boot disks, as I'm able to do a network install.

The situation is we are encorporating in our mirror (for stanford people)
all updates into the generic redhat install tree, e.g. we replace
the RedHat/RPMS/kernel-2.2.14-5.0.i386.rpm with
RedHat/RPMS/kernel-2.2.14-12.i386.rpm and then rerun genhdlist.

Though non-standard, it does appear to be a bug in the redhat compile.
You should be able to install all the fixed rpm's without installing the
ones with bugs (IMHO).  The idea is if you install redhat today, you've
installed the latest system, and don't have to immediately go back and
apply updates.