"Unable to Mount XXXX. DBus error org.freedesktop.DBus.Error.NoReply: Message did not receive a reply (timeout by message bus)"
Steps to fix the problem:
1. Install libimobiledevice1 from the ppa:pmcenery/ppa repository
sudo add-apt-repository ppa:pmcenery/ppa
sudo apt-get update
sudo apt-get dist-upgrade
gksudo synaptic
2. Unpair the device using idevicepair from the libimobiledevice-utils package
idevicepair unpair
Refs:
http://libiphone.lighthouseapp.com/projects/27916/tickets/183-cannon-mount-iphone-with-ios-421-in-ubuntu-1010
https://help.ubuntu.com/community/PortableDevices/iPhone#Device does not mount after iOS4.2.x upgrade
