Here is the bulletin that logged some similar issues that customers experienced last week(http://community.landesk.com/support/docs/DOC-4510). The common issues were the wrong filter setting for viewing, the vulnerability was in the wrong folder, or there were some dependencies that we were not being scanned which resulted in no scanning activity. If you have the MS08-078_VISTA_WIN2008 then you should have the MS08-078 vulnerability definition as well. I would look in the All Items node in the Security and Patch Manager treeview and make sure that the filter settings are set to All Items. If you still cannot find the vulnerability I would open a trouble ticket with our support group.