Connie, Troy,

As I said in more-detailed mail to Troy: what I really wanted to
do on this occasion was quite simple - I wanted to add an extra
kernel-module[1], without changing my current kernel.

[I assure you that I have built custom kernels many times before, with
reasonable success, but on this occasion I really didn't want to build
the kernel itself.]

Well, the build procedure for this kernel module is evidently only
intended to build for the running kernel, and it seems to rely on
having a compatible source tree and .config

OK, it seems the source tree must have been in an incompatible state,
even though I hadn't actually used it for doing any kernel building.
(I'm sorry to say that I panicked and reported that it could not build
the kernel either.  This wasn't true.  When I calmly took it step by
step, I *was* able to build a custom kernel.  But I didn't really want
a custom kernel on this occasion).

Anyhow, here's what I did to "solve" the original problem: I deleted
the kernel source rpm, and then installed it again.  And then copied
the /boot/config* file to /usr/src/linux-2.4/.config

And now my kernelmodule build is going fine, and the resulting
ndiswrapper kernel module is evidently working (it has communicated
with the Wireless AP, and registered for DHCP and all...)

I don't claim that this is exactly the right thing to do, but it seems
to have got things working, for now.

thanks

[1] http://ndiswrapper.sourceforge.net/
It's for running wireless cards that are unsupported by linux.