Probably your setup is not correctly configured or some packages are missing. Did you followed the instructions in the page that I posted here ?
You also need, at least, 'qtlib4-maemo5-maemo5', try also to compile your app directly under scratchbox to see if the problem is in your esbox setup, don't forget to use qmake under '/opt/qt4-maemo5/bin/qmake' since you're running Qt 4.6.