mouse over button - What's Wrong

BMAP* cursorImage = "cursor.pcx";
PANEL* panel_testButton =
{
	layer = 100;
	scale_x = 0.7;
	scale_y = 0.7;
	button (0, 0, "test.tga", "test.tga", "test_light.tga", NULL, NULL, NULL); 
	flags = OVERLAY | TRANSLUCENT;
	alpha = 100;
}

function main()
{
	mouse_map = cursorImage; //set the mouse pointer bitmap
	mouse_mode = 2; // use mouse
	
	// set the rotation center at the panel center
	panel_testButton.center_x = panel_testButton.size_x * 0.5;
	panel_testButton.center_y = panel_testButton.size_y * 0.5;
	// set the size of the button
	panel_testButton.size_x = panel_testButton.center_x * 1.6;
	panel_testButton.size_y = panel_testButton.center_y * 1.6;
	// set position
	panel_testButton.pos_x = (screen_size.x)/2-50;
	panel_testButton.pos_y = (screen_size.y)/2+200;
	
	// start loop
	while(1)
	{
		
		// mouse cursor pos
		mouse_pos.x = mouse_cursor.x; // allow the mouse pointer to move
		mouse_pos.y = mouse_cursor.y; // on the x and y axis
		wait(1); //loop
	}
}