Check your Preferences.
In particular, look at the Library tab and verify that the paths for 'Installation Folder for Packs', 'Location of Live 8 Library' (if set) and 'Location of User Library' are all set to existing locations.
If they're not, either find the correct paths and set, or reinstall the library (no biggie).
With regard to MIDI controllers, well go to the MIDI Sync tab and do the same. Verify that all of your control surfaces are selected and their inputs and output are assigned. Then verify that all of your MIDI ports are visible for your devices and Track, Sync and Remote are set to your specs.
And if you don't see your devices here, then check your system to ensure that the devices are being recognised by your OS... etc.
Beyond that, log a support ticket with Ableton