Last night I had to execute the MVM installation binary in order to "Repair" the MVM installation. After the repair MVM updated seemingly everything with the lastest 7.5.6.
Today, I am trying to execute a scan, but it is futile because seemingly the theat DB is not updated. When I login to MVM and go to Reports -> Threats the latest update is from April 19, 2012. The update manager updates all components and has the latest according to the Configuration Manager and Update MVM.