I'm still trying to make my old 5.3.8 version work but as you seems 
to consider that an upgrade is necessary, I'm trying to install 
a 5.3.15 coda server on another box
(rpm -ivh coda-debug-server-5.3.15-1.i386.rpm)

Doing so, I got  :

"error: failed dependencies:
        libreadline.so.3 is needed by coda-debug-server-5.3.15-1
        libstdc++.so.2.8 is needed by coda-debug-server-5.3.15-1"

I can't install the readline2.2.1-2.2.1-2.src.rpm
or any other readline rpm containing libreadline.so.3
beccause there's a conflict with the my readline-4.1-15mdk
(installed by default with my Mandrake 8.0)

I know it's not directly relating to CODA, but as I'm not a linux share lib
expert
and as you must have gone into those problems I hope you'll give me some
hints.

I first thought to uninstall readline2.2.1-2.2.1-2.src.rpm, then install
readline2.2.1-2.2.1-2.src.rpm,
then upgrade to readline2.2.1-2.2.1-2.src.rpm (to have both
libreadline.so.3 and libreadline.so.4)
But it seems a little bit "dirty" (even for me ;-)
What it's the correct/clean way to handle problems like these...
(I guess libstdc++.so.2.8 will cause me the same troubles...)

Regards.