Looks like with Ubuntu 9.10 you have to install IPv6 support in perl. Not sure why this is the case, maybe something f'd up during the upgrade! Here's what worked for me:
run perl -mIO::Socket::INET6 -e ''
if it returns "Can't locate IO/Socket/INET6.pm in @INC ", then you need to install the perl module.
perl -MCPAN -e shell
cpan> install IO::Socket::INET6
Here's where I found the info: http://forums.cpanel.net/f5/spamassa...ry-128705.html