This article is from the Frequently Asked Questions for Linux, the Free/Open Source UNIX-like operating system kernel that runs on many modern computer systems. Maintained by David C. Merrill with numerous contributions by others. (v1.0).
A: You are trying to use the old network configuration utilities. The new ones can be found on ftp://ftp.linux.org.uk/pub/linux/Networking/PROGRAMS/ NetTools/ (source only, I'm afraid).
Note that they cannot be used just like the old-style programs. See the NET-2 HOWTO for instructions on how to set up the old-style networking programs correctly. Even better, see the NET-3 HOWTO and upgrade your networking software.