I get some similar troubles with fetchmail; I had given up on it. I am using fetchmail to connect to a VAX/VMS server.
When I run fetchmail -u blah servername I get no output, no delivered mail messages, nothing at all. When I run (less naively) fetchmail -vv -b5 -B5 -p POP3 -u blah servername On this command, when fetchmail in slink began to download the first message, it would fail with 'realloc failed'. I upgraded to the potato version, and now I get segfaults instead. So you may want to try the -vv and see if you can diagnose the error that way. (note...) When I tried to strace the potato version, what I saw was an apparently infinite loop of mremap calls, each asking for a little more space. I had a 41meg typescript full of mremap calls. I had decided to let it drop for a while, then I was going to try to downgrade to the hamm version and give that a try. Carl