$ export LUAINPUTS=/usr/share/texmf/scripts/context/lua//
You might have to add a second directory (see http://www.ntg.nl/pipermail/ntg-context/2007/026272.html), but there is a much simpler way, see below:
Desperate as I am I did put the above LUAINPUTS line into the texmf.cnf,
This should not make any difference, so it's quite lucky that it doesn't ;-)
How are you guys setting up your system??? Is this magic? Or is there nobody else besides you two actually using/trying it out???
Download http://www.pragma-ade.com/context/install/linuxtex.zip (or whatever is appropriate for your system) and source setuptex. That's really all you have to do if you use the minimal ConTeXt distribution; and of course you can adapt it to suit your needs, just have a look at it. The first half of the script tries to identify the topmost directory of your installation with some simple heuristics (it calls it TEXROOT), and the other half then sets all necessary variables accordingly. Arthur