I have recently updated my RH9(kernel 2.4.20-8) to kernel 2.6.14.3. but an error occurred when I tried to configure a new connection. the error message is
TB/usr/src/build/226257-noarch/install/usr/share/
redhat-config-network/netconfpkg/NC_functions.py:119:
rpms_notinstalled:TypeError: rpmdb open failed.

Also, I failed to initialize iptables(version 1.2.7) on startup.
Are 2 problems related and What should I do to fix the bugs?
Please help me. Thanks very much.

Regards
WrH

Doing just the kernel will leave many programmes unable to work, especially those compiled against the specific kernel, eg modprobe, iptables..

I suggest you stay with your old kernel version number and patch your older kernel sources up to the current 2.4.x version. You can have a 2.4.30 kernel and still call it 2.4.20-8 when you build it.

Either way, you are going to end up with an orphaned system as security updates have stopped for all packages, or you will have to compile everything yourself.
It may be time to leave RH9 and use a fresher distro..