Why won't this tutorial work?

I’m trying to work through and recreate a tutorial (attached, attribution in file), but it appears that the final evaluation (a Manipulate plot) no longer works. Can someone help me figure out why this is? I’ve attached both the Mathematica notebook and the PDF, the latter of which shows the working plot. I know that the legends stuff is out of date (I believe the tutorial was written for Mathematica 7), but removing PlotLegends et al doesn’t resolve the problem. Please help!

It works for me if I comment out the calls to the PlotLegends functions as well as commenting out the loading of the PlotLegends packages. See the attached.

Perfect! I never would’ve thought it’d be that simple. Thanks a million!