Do you have access to the Internet when you run the scan. MBSA will try to update the file by default
There is a little check box in MBSA when you set the target scan parameters, which allows you to check or not check for 'Check for security updates'. If that box is unchecked then MBSA will not try to update the XML file
The XML file is updated when the app runs to make sure that MBSA is looking for the latest set of signatures i.e. vulnerabilities, etc. If the file is not up-2-date then you're basically checking a system against an old set of vulnerabilities and application signatures
Hope that answers your question..
- V
