Error script no-value
An attempt was made to evaluate an undefined word
This is a script error.
Within the current context, REBOL could find no value for the given word.
All the juicy details about this kind of error go here.
The community can contribute to it too and provide examples with deeper explanations.
We will probably want some kind of standard format for these.
Also, I wrote a pile of explanations for them a while back on REBOL.com. I will provide those as a starting point.
And finally... I'm not so sure mediawiki is the very best way to handle them... but it is a start.