It has come to my attention that running XP in VBox and using iTunes in XP, can fail seriously in a lot of situations.
Apparently it is due to some changes in the iTunes software, and how it checks for virtualisation.
1. Back down the iTunes software to version 9.0.2 Prevent it from updating.
All should be well.
2. If your BIOS allows you to turn on Virtualisation then do so.
This should allow the later iTunes software to run.
I have not checked this but it is reported to work. A lot of BIOS's do not give the user access to such settings, in which case solution #1 seems to be the only way forward presently.