Something must be up with your photos because when I try the photos that come with the photo gallery it works just fine (I copied and pasted the code from the tutorial as well, just to be sure) but your photos don’t work in either your gallery or the tutorial gallery.
One thing I noticed which doesn’t really make a difference with the photos but is something to pay attention to - the tutorial recommends creating the photo MC at the same size as your images. I noticed you had it set to 250 x 175, the same as in the tutorial, but your images were 432 x 324 (or something like that). Anyway, just something to look at.
I would recommend trying sbeeners tutorial files (you can download them at the bottom of the tutorial) with some other images of yours (rename them “image0”, “image1”, etc.) to make sure they work in a file you know works before transfering them to your own project.
Sorry I couldn’t help more but I do think the problem is something funky going on with your images, not your fla. Is that good news or bad news?