Urgent : gluPickMatrix with Visual C++ 6.0

I need some help because I have an urgent project to do and I have a problem with the picking. In fact, these 3 lines heve been given to me by experienced users but they used glut and not VC++ :
GLint viewport [4];
glGetIntegerv (GL_VIEWPORT, viewport);
gluPickMatrix (xmouse, viewport [3] - ymouse, 1., 1., viewport);

i think it’s a window coordinate problem.

I hope you can help me.


PS: sorry for my bad english but i’m french