We had a machine that had multiple problems when upgrading from Ubuntu 12.04 to 14.04. Most of the problems were related to the user having installed OpenOffice packages on top of LibreOffice and causing problems in the standard upgrade. Once those were handled though the system was left in an unusable state and wouldn't upgrade or install the required bluez packages and ia32-libs.
Well it turned out that Bluez wouldn't properly install because dbus had failed to start while we were fixing other packages. Once we ran:
service dbus restart
then the "apt-get install -f" would finally finish and all was well.