Detecting that a Novell client is in use

Hi there

I'm currently writing a script for a setup program (in Inno
Setup for 
those who know it).
The program I have to instal has a particularity (I have to
add 2 dll 
during the installation process) when running in a Netware
environment 
with a Novell client (can be under 9x, Me, NT4, 2K or XP).
My problem is to detect if a Novell client is in use on the
computer, 
how can I detect this? registry key or value?

Thanks in advance

Phil