The conduit logs show that an network error "42" is occuring and that the anti-spam rule sets have not been updated.
2011-02-07T16:08:23-08:00 (INFO:23915.3060770496):  Request failed: ruleset=rules url=https://aztec.brightmail.com/rules2/spamhunter.vcdiff/4/1297109413 curl_status=42
2011-02-07T16:08:23-08:00 (ERROR:23915.3060770496):  Network error occurred, Callback aborted (42), check your network connection settings, check your proxy settings (if applicable), and check to ensure that port 443 (HTTPS) is open through any relevant firewalls.
Please check your firewall and confirm that SMG can connect to the internet on port 443 to download anti-spam rules. If you are using a proxy server, please confirm that the configured proxy server is available and is not attempting to do TLS inspection on the SMG connections to the rule download servers.