there should only be one at most. What happens when you try to run qmake -project. Remember that the folder the source is in should have the same name as the main source file. If you wrote the code using KDevelop there should be a src directory within the project folder. The source files would be in there. Copy them into a directory with the same name as the main source file then run qmake as I described above.
Make sure you run the qmake -main.pro step where main is the name of the folder the source is in. This will develop a Makefile you can then compile with make.