You need the "bubble" layer to be in front of the image layer.
There's probably a "promote layer" or "bring forward layer" option somewhere in the menus.
If not, look in the help section for "layers".
What's happening now is the bubble text is "in front" of the original image, but the bubble background is "behind" it -- this might take a bit of getting used to as you may end up having the white background in front of the text when you start fiddling - which of course makes the text disappear
HTH