Radio Shack's little boards use edge numbers to assist in placement of components (marketing gimmick, I think). Notice that on the component side, the lines are consecutively numbered 1 though 30. On the flip side, they are shown by five's.
If you look carefully, it appears the "top" of those two resistors in the trigger lead (at positions 15 or 16 and about 20-something) are soldered to his ground bus. This would sure account for the problem.
A 555 in mono when triggered will stay high until the trigger returns to high despite the timing. It's kinda like Tennessee's basketball team at tournament time - one and done.
A multimeter between pin 3 and ground should show a continuous positive voltage right from power-up if I am correct.