Please be informed that the Microsoft Baseline Security Analyzer (MBSA) v1.2.1 will be discontinued on March 31, 2006. After this date, MBSA 1.2.1 will no longer be supported and the MSSecure.xml file that is automatically downloaded by MBSA 1.2 will no longer be updated to include new security bulletins. Microsoft encourage you to migrate to MBSA 2.0 before this date to guarantee continued security bulletin detection.
More info in Microsoft KB895660 and in Microsoft Baseline Security Analyzer page.