wheel - 4:31 pm on Jul 6, 2011 (gmt 0)
And it wouldn't make sense for these 404s to hurt your site since they originate from other domains.
Then I've misunderstood.
If A points to B, and the links are broken, then I agree - no affect on B, B doesn't care.
But IMO, A should care. I think it's bad if your site has lots of outgoing broken links.
I'd understood the OP was in control of both the originating and destination sites. If you're not in control of A, then I'd just go back to sleep and forget about it.