How to install Qt/E correctly?

I'm using Ubuntu and I have installed Qt/X11 from qt.nokia.com.

when I install Qt/E I have met the error: XLib test failed after "./configure".

Basic XLib functionality test failed!
You might need to modify the include and library search paths by editing
QMAKE_INCDIR_X11 and QMAKE_LIBDIR_X11 in /home/lolveley/bin/qt-x11-opensource-src-4.5.1/mkspecs/linux-g++.

SOLUTION:
sudo apt-get build-dep qt4-qmake