You could put together a report with errors found in the code with the name of the programmer that was responsible for that piece of software.
If he's a reasonable person, discuss the report with him.
If he cares for his "reputation" publish the report regularly and make it available to all his peers.
If he only listens to the "authority", do the report and escalate the issue to his manager.
Anyway, I've seen often that when people are made aware of how bad they seem from outside, they change their behaviour.
Hey this reminds me of something I read on xkcd :)
