This is likely where you've already performed the alignment, taxied, then changed the runway and mistakenly entered the wrong runway/airport (ie: activated secondary with different flight plan or opposite runway which is far enough away to set of the warning) Of course, there are other possible reasons
Basically, the two systems are separate - IR (ADIRU) and FM - but they communicate with each other and spit out messages when they get confused.
You'd get a theoretically similar message if you entered the wrong ILS frequency for a departure runway which had an ILS in the database.
Understand?