No worries, I've attached a zip file that contains the file.
Open REAPER and go to the Actions window. Run the Action:
Show REAPER resource path in Explorer
Then download the zip file, double click to open and drag and drop the file it contains into the "Effects" subdirectory in the folder that Reaper opened.
In the Data subdirectory at that location create another folder called "pc_mapper" and create a .txt file in there with some entries and the script should pick it up automagically when you put it on a track.