unable to include header file

Hello

I have made a class in Qt4 using Kdevelop.I included Qwt in my program but it is showing the error that "can include QwtPlot.h".what is the error?Qt 4 runs very well with KDevelop.I have set the path of Qwt library also?
Is there any problem in my Path set?
how can I integrate Qwt-5.0.1 with Qt4.2?
Please help

Did you also set the path for the header files of Qwt ?

On Linux, they should be located in /usr/include/qwt-qt4, if I remember well :)