One definite issue I have found that gives the 'write delay' error is when you use up all of your space on your computer's hard drive with your xml and xtl files from Itunes. This relates to when you are on a network that limits your 'my documents' space. I moved my actual library to a location on my harddrive, however the xml and xtl files will always remain in the 'my documents' folder by default. This sucks by the way and it would be great if Itunes would let you move those files as well. If your library is very large (mine is 69 gigs), the xml/xtls combined can take up a great deal of space (about 40 mb in my case). I have yet to find a way to overwrite the xml/xtl location.
I know this is not the same problem, but I wanted to put it out there as a possible related problem.