Elementary "hello" program doesn't build

[DrunkenUFOPilot]

Both Qt4 and Qt3 are on this machine. Well then, how to tell qmake to use 4 not 3?

[nish]

Both Qt4 and Qt3 are on this machine. Well then, how to tell qmake to use 4 not 3?

try to use qt4-qmake instead of qmake or install the sdk, and run qmake from full path, eg ~/qtsdk/qt/bin/qmake.

[wysota]

Both Qt4 and Qt3 are on this machine. Well then, how to tell qmake to use 4 not 3?

You don't "tell" qmake to use Qt4. You have two qmake binaries - one for Qt3 and one for Qt4. The proper one can be called qmake-qt4.