I am adding this here mostly for my own reference but if you need to test your app using the Opera Mini emulator on Ubuntu this is how you fix the QtGui error:
./opera-mobile-emulator-launcher: error while loading shared libraries: libQtGui.so.4: cannot open shared object file: No such file or directory
It turns out the emulator required the 32 bit
libqtgui package to run
sudo apt-get install libqtgui4:i386
Of course this error only occurs if you are running 64 bit Ubuntu.