[ILUG] When to fix a driver/when to upgrade a kernel?

[Dermot Daly]

HI Guys,
I attempted to compile the ZyXel 630-11 USB ADSL Modem driver under
Fedora Core 1 last night, using Caolan's HOWTO.  I ran into a number of
problems. (see below)
1. Initially, the make did not realise that the stock installed kernel
(which is a 2.4.22 Kernel) included loadable module support. This
appears to be caused by the fact that I have never compiled my kernel
(really just installed it from the Fedora CDs). By running make
oldconfig from /usr/src/Linux2.4 generated the .config file, and the
make could now go further.
2. However, br2684ctl.c does not compile (with missing #defines by the
looks of it).
3. I tried doing a make dep from /usr/src/Linux2.4 and this makes things
even worse.

My questions are:
How do I know whether I should change my Kernel, or try to fix the
#includes in the code which obviously do not seem to match my kernel
source?  
When is it a case of "it will not work with that version"?
If I do have to upgrade by kernel to a 2.6 can I do this using rpm ?
Where would I get the kernel 2.6 RPM and Source RPM?
TIA
Dermot.