Oct 2009 and iPod still has this 1439 error, I have Windows XP.
I tried for 3 weeks with different options and still not sure what caused this but here's some solutions.
iTunes 9 is unstable and could've caused the ipod to freeze, I reverted back to iTunes 7
Also could've been caused transferring to iPod converted videos, I was advised in future, convert 1 at a time to avoid conflict/overlap of data.
Finally the solution that worked, I unplugged printer and webcam and plugged ipod into back of PC and it restored in less than 5 minutes. My arrogance prevented me from trying something soooo simple!!
I did lose all my music but still have it on PC so no drama there, time for an overhaul anyway.
Good luck to others, hope this helps