Drag and Drop Bug (Flash, AS3)

Hello! Help, please! I'm making a game that involves dragging and dropping books. (Right now there is only one book.) While testing my game, I discovered by accident that no matter where I drag on the screen, the draggable book responds, moving around on screen despite the cursor not being on top of it. Here is my code. (It also snaps a larger book mc to the small one for purposes I intend to use later.)

// Making the small book dragable. //

small_book.addEventListener(MouseEvent.MOUSE_DOWN, fl_ClickToDrag_6);

// when the mouse button is clicked...

function fl_ClickToDrag_6(event:MouseEvent):void

{

    small_book.startDrag();

    big_book_mc.x = small_book.x;///

    big_book_mc.y = small_book.y;///-----> Makes the big book snap to the lil one when clicked.

}

stage.addEventListener(MouseEvent.MOUSE_UP, fl_ReleaseToDrop_6);

// when the mouse button is released...;

function fl_ReleaseToDrop_6(event:MouseEvent):void

{

    small_book.stopDrag();

    big_book_mc.x = small_book.x;///

    big_book_mc.y = small_book.y;///-----> Makes the big book snap to the lil one when the mouse button is released.

}

stage.addEventListener(MouseEvent.MOUSE_DOWN, dragFn);

// if the mouse is currently dragging....;

function dragFn(event:MouseEvent):void

{

    small_book.startDrag();

    big_book_mc.x = small_book.x;///

    big_book_mc.y = small_book.y;///-----> The big book follows while the mouse is dragging.

}

// the small book is now draggable and the big book snaps to it.