Comment 25 for bug 812104

Tested but unfortunately didn't help here :|
this is a oneiric virtualbox installation with your ppa:

$ sudo dpkg -l | grep qt4
ii libqt4-dbus 4:4.7.4-0ubuntu8ppa2 Qt 4 D-Bus module
ii libqt4-declarative 4:4.7.4-0ubuntu8ppa2 Qt 4 Declarative module
ii libqt4-network 4:4.7.4-0ubuntu8ppa2 Qt 4 network module
ii libqt4-opengl 4:4.7.4-0ubuntu8ppa2 Qt 4 OpenGL module
ii libqt4-script 4:4.7.4-0ubuntu8ppa2 Qt 4 script module
ii libqt4-sql 4:4.7.4-0ubuntu8ppa2 Qt 4 SQL module
ii libqt4-sql-mysql 4:4.7.4-0ubuntu8ppa2 Qt 4 MySQL database driver
ii libqt4-svg 4:4.7.4-0ubuntu8ppa2 Qt 4 SVG module
ii libqt4-xml 4:4.7.4-0ubuntu8ppa2 Qt 4 XML module
ii libqt4-xmlpatterns 4:4.7.4-0ubuntu8ppa2 Qt 4 XML patterns module

$ sudo dpkg -l | grep unity-2d
ii libunity-2d-private0 4.12.0-0ubuntu1.1ppa1 Unity 2D shared library
ii unity-2d 4.12.0-0ubuntu1.1ppa1 Unity interface for non-accelerated graphics cards
ii unity-2d-launcher 4.12.0-0ubuntu1.1ppa1 Unity 2D Launcher
ii unity-2d-panel 4.12.0-0ubuntu1.1ppa1 Unity 2D Panel
ii unity-2d-places 4.12.0-0ubuntu1.1ppa1 Unity 2D Places
ii unity-2d-spread 4.12.0-0ubuntu1.1ppa1 Unity 2D Spread

attached also a screencast, hope this help you