The first suggests deauthorizing and reauthorizing your computer. The second suggests updating drivers and uninstalling / reinstalling iTunes. If it does it partly during the sync, you can try setting it to manual sync and only select a few things to see if it's something wrong in your iTunes library.
Probably because you're running it under Windows. Apple intends iTunes to be a glass of ice water in the hell that is Windows but occasionally they fill the glass with something other than water just to remind you that buying a Mac is a good idea.
It's the same reason why Microsoft makes Outlook and Office worse for the Mac than for Windows.