I see thousands of these in my Console log
This could happen for a number of reasons, one of those could be that you unplugged a FireWire drive while spotlight was indexing it. You may have to reset spotlight indexes to stop the error appearing if this has happened. You can do so with the Terminal command below. 

sudo mdutil -E /

Spotlight will need to reindex all your drives which will take some time, allow it to finish indexing each drive before unplugging it and that may solve the problem

See the link below for an article from someone with a similar issue who solved it performing the steps above  

http://www.mb.com.ph/articles/209838/the-case-missing-firewire-port