| Check iTunes logs:
win7- C:\Users\<UserName>\AppData\Roaming\AppleComputer\ Logs
C:\Users\<UserName>\AppData\Roaming\Apple Computer\iTunes\iPhone Updater Logs
winXP- C:\Documents and Settings\<UserName>\Application Data\Apple Computer\iTunes\Logs
C:\Documents and Settings\<UserName>\Application Data\Apple Computer\iTunes\iTunes\iPhone Updater Logs
Last lines can explain the problem.
Have you tried update on another computer?
I had a 4012 error and it was coused by errors at the windows registry. On another computer it worked perfectly |