Did you see Shoghi's response? The error is asking you to do your Restore from the Object level, not the session level. He is correct, the Help -> Help Topics, when you search for 'Restore Sessions', ranked #3 is an article that includes this:
You cannot perform restore of the online database integrations from a specific backup session.
It is not stated wht type of backup that this was, it is fairly easy to find out by running the command
omnidb -session 2014/01/20-2 -detail
the Backup Type line will tell you what type of backup. if it says anything other than '-filesystem' (for UNIX backups), or '-winfs' (for Windows Backups, you cannot use 'Restore Session'
This is a pretty generic error, it can also apply if there was no protection on the backup
