Go to HD>Library >Audio>MIDI Drivers and right click on the EmagicUSBMIDIDriver.plugin >Show Package contents >and open info.plist you should be able to see if the drivers you just installed are the latest
the recent ones are version 2.2. not sure if the ones you installed are the current ones ..so check that
or
Try the drivers on the DVD (deselect everything but the drivers box..-fyi it won't work if you try installing them from within the packages folder)..
A
PS: if the EmagicUSBMIDIDriver.plugin looks like an AU component click to open it ...Logic will start and hopefully AMT will be alive again