Dear All
               It looks as if we've split into two camps on this. Laurel and I want to go for 'veldr' meaning 'he is not at fault', but I think (certainly in my case) that, failing help from the dictionary, we are trying to find a translation for 'veldr' which would make the proverb furnish us with a sentiment appropriate to the context.
 
However Eirich's interpretation of 'veldr' as 'that he doesn't cause',  looks good if we are allowed to supply something to be understood. If so, we could end up with 'he doesn't cause the trouble/problem/wrongdoing .....who warns another.'  In modern parlance Hrafnkell is saying 'You can't blame a man for doing something harmful to somebody if he has already warned him of the likely consequences of his actions'. This amounts to the same interpretation that Laura and I have come with, but Eirich's approach is the proper one because he is true to the dictionary's definition of 'valda'.  Am I right or wrong? Comments welcome.
Cheers, 
Jed.