Z-buffer picking, gluUnProject picking not working

[Icetigris]

I'm having a lot of problems trying to get picking to work in jogl in CentOS 5 (RedHat). I have a lot of pickable cubes on screen and I need to be able to pick one. Right now, glRenderMode(GL_RENDER) returns -1 or 0. When I comment out glRenderMode(GL_SELECT), I do sometimes get something drawn on screen, but it is usually not from where I clicked. It appears that, when I am not commenting out glRenderMode(GL_SELECT), the return value of -1 is when nothing is drawn when it is commented out and the return value of 0 is when something incorrect is drawn. In the place with the commented out gluUnproject, gluUnproject returns 0,0,0 on every click.

Here is my pick function:

    public void pick(GL gl)
    {
        if(mouseLeftClicked)
        {
            System.out.println("you clicked your mouse and are attempting to pick something");
            IntBuffer selectionBuffer = BufferUtil.newIntBuffer(BUFSIZE);
            int hits = 0;
            double[] worldCoords = new double[3];
            IntBuffer viewport = BufferUtil.newIntBuffer(4);  
            FloatBuffer modelview = BufferUtil.newFloatBuffer(16);
            FloatBuffer projection = BufferUtil.newFloatBuffer(16);
 
            DoubleBuffer objectPosition = BufferUtil.newDoubleBuffer(3);
 
            gl.glGetIntegerv(GL.GL_VIEWPORT, viewport); //save viewport into buffer
            gl.glGetFloatv(GL.GL_PROJECTION, projection); //save projection matrix into buffer
            gl.glGetFloatv(GL.GL_PROJECTION, modelview); //save modelview matrix into buffer
 
            viewport.rewind();
            projection.rewind();
            modelview.rewind();
            objectPosition.rewind();
 
            gl.glSelectBuffer(hits, selectionBuffer); //setup hits buffer
 
            int realY = viewport.get(3) - winHeight -1;
            gl.glRenderMode(GL.GL_SELECT); //put gl context into selection mode
            gl.glInitNames(); //initialise name stack
            gl.glPushName(0);
 
            gl.glMatrixMode(GL.GL_PROJECTION);
            gl.glPushMatrix();
 
                gl.glLoadIdentity();
                glu.gluPickMatrix(mouseX, viewport.get(3) - mouseY, pickWidth, pickHeight, viewport);
                glu.gluPerspective(45.0f, ((float)winWidth/(float)winHeight), 1.0, 50.0);  
 
                gl.glMatrixMode(GL.GL_MODELVIEW);
 
                //cube.drawCubes(gl);
                //gl.glLoadName(1);
                c.draw(gl);
 
                gl.glMatrixMode(GL.GL_PROJECTION);
 
            gl.glPopMatrix();
 
            gl.glMatrixMode(GL.GL_MODELVIEW);
 
            gl.glFlush();
            hits = gl.glRenderMode(GL.GL_RENDER);
 
//            glu.gluUnProject(winWidth, realY, 10.0f, modelview, projection, viewport, objectPosition);
 
            processHits(hits, selectionBuffer);
 
            mouseLeftClicked = false;
            System.out.println("oh we got to the end of picking; selectionBuffer has " + selectionBuffer.capacity() + " elements");
//            System.out.println("gluUnProject results: x: " + objectPosition.get(0) + " y: " + objectPosition.get(1) + " z: " + objectPosition.get(2));
        }
    }

[Icetigris]

I got the return values sorted out, but now when I click, it doesn't always register a hit. It's especially bad when I rotate my scene.