preferred implementation for error reporting

Hi,

I've been trying to debug a rather lengthy RNG and am running up against 
the somewhat enigmatic errors reported by most implementations... If I 
run both jing and xmllint I tend to get a feel for what's wrong but it's 
still far from ideal.

So before I go hunting, is there an implementation of RNG that has 
precise error reporting?

-- 
Robin Berjon
   Research Scientist
   Expway, http://expway.com/