This is an interesting one... no clue how to fix it, but I should be able to track it down.
Oct 9 14:54:16 pro-38-gl stunnel: LOG3[5026:3081313168]: remote socket: Address family not supported by protocol (97)
I'm using stunnel to proxy via a two link chain of polipo caching proxies. Fun, huh?
UPDATE: I think this was caused by a wget command which was using the all_proxy environmental variable when it should have just been going direct.
Anyway, I've setup a local squid server to only connect via stunnel if necessary.