There's a bug with 10.1.0.54, Mikey, that is causing "iTunes has stopped working messages" (citing CoreAudioToolbox.dll in the Problem Reports for the error) for some folks when importing CDs with the AAC encoding, adding/converting files to AAC, and in some cases syncing devices (when the convert to 128 kbps AAC option is enabled).
Short of rolling back your iTunes to 10.0.1.22 and your Apple Application Support to 1.3.2 (CoreAudioToolbox.dll is kept in the Apple Application Support program files), there's a few possible workarounds.
(1) Change your importing prefs to use a different encoding (won't help with the device syncing variation though), and/or disable the convert to 128 kbps AAC when syncing option.
(2) Replace your CoreAudioToolbox.dll version 7.9.4.0 with a 7.9.3.0 as per:
http://discussions.apple.com/thread.jspa?messageID=12576816#12576816
(3) Or, replace your CoreAudioToolbox.dll version 7.9.4.0 with a shadow copy of a 7.9.3.0 as per:
http://discussions.apple.com/thread.jspa?messageID=12583499�
(4) Or, if no known-good copy of 7.9.3.0 is available and your PC doesn't have a shadow copy of the 7.9.3.0, you can replace your CoreAudioToolbox.dll version 7.9.4.0 with a 7.9.3.0 by performing some installation gymnastics with the current (11 am 18 Nov NZ time) version of the Safari 5.0.2 installer, as per:
http://discussions.apple.com/thread.jspa?messageID=12598386�
NB with (4) if you have a 64-bit version of Vista or 7 ... the Apple Application Support program files are instead located at:
C:\Program Files (x86)\Common Files\Apple\Apple Application Support\
(2, 3 and 4 do help with the device-syncing variation.)