Hiya jflatto,
just had the same problem myself.
What you'll find is that unzipping the file creates a folder named something like RB_SH4_effects_for_SH3_2_03, or something like that. Actually the name i just quoted was for the inner file, after you've opened the outer file.
Properties will tell you that both files are 74.5mb, but the outer file is no more than a shell for the inner file, and the inner file contains the graphics files, but also the optional folders, help docs etc.
This inner file, when opened, contains yet another file with a similar name, called Racerboy_SH4 effects_for SH3, as opposed to RB_SH4_effects etc. This file is 41.4mb, and it's the one you want.
Basically theres a folder within a folder, within another folder, all with very similar names, and it's the innermost folder you want lol
I suggest you unzip the file anywhere you want to store the optional and help files, but i'd avoid unzipping it in the SH3 folder.
When you've unzipped it open it, then open the inner file and look for the Racerboy file of 41.4 mb.
Put this file in the MODS folder and run JSGME.
Then it should work.
Happy hunting
