I have the same problem with my Book World Edition II (White Light).
I have only had it for just over a year and now a specific function that I purchased it for (apart from a network backup drive) has stopped.
It may not be WDs fault but I bet WD will fix this for current models, so why not past ones that are such recent models.
N.B. I have meanwhile turned off the iTunes server function, but the drive continues to publish its presence in iTunes. Even more annoying that I cannot stop the error being displayed.