Bingo - exactly what I get too, even a local core secondary hard drive constantly keeps producing these messages, so my original theory that there may be a network error that made the NAS keep re-presenting itself, seems to be out the window as it is even doing it on local drives. I have completely rebuilt the core from scratch (using the single DVD disk approach) and it does the same thing.
It seems to settle down for a while then starts doing the same thing again - the number that comes with the message, which seems to just increment like an index number, ends up in the many thousands...