Quote Originally Posted by jacek View Post
These errors are really weird. Does it compile if you invoke "make -f Makefile.Release"?

Did you compile the debug version of Qt libraries yourself?
sorry i can't test your suggestion, because i formated the computer and made a clean installation of everything but visual studio....now i re-wrote the same code and it worked!!!

i hope that i can now finish the book on qt4 without any problems...

thanks again for your help!!!