Which files did you download? It's not just the .jsfx files you need - there are a couple of extra libraries that are also in that directory, one of which helps draw the graphics.
The simplest way to get everything you need is to use the
ZIP from the stash, which should have everything included. (There's also a ReaPack package, if that's something you use.)
Give me a shout if that doesn't work for you.