Thanks Wysota for your response.

What's the purpose of wanting to copy all the sources and project file into current directory? What's the purpose of trying to copy the target executable to a "Demo" directory?
I am doing same on another system. previously i was unaware about Qt creator and designed forms in Qt Designer, write .cpp and .h files for forms and used qmake and make commands to compile and link the application.
Now i am using Qt creator and want to load and compile the old projects with Qt creator which are on another system (old means 7 days old, i have started Qt 7 days ago).

What does /usr/include/qt4/QtGui contain?
/usr/include not contains any folder named Qt4 ot Qt. /usr/lib contains a folder named Qt4.

What does qmake -v return?
it is returning
QMake version 2.01a
Using Qt version 4.7.4 in /usr/lib/i386-linux-gnu

Thanks.