Hmmm.... sorry to hear that. I just tried the MacWorld one on a system I am working on since I had never tried it with 10.5.6, but it worked fine. Did the killall Dock and there it was.
If I may ask, at which point did they fail? By that I mean did it throw an error when the line was pasted into Terminal, or did it just not appear after the killall Dock was entered into Terminal or ....? This does have me curious!😉