I've copied the three files from the railworks folder to the rw_tools folder as indicated in the help file, I've set all files in the railworks folder to not be read-only, and I re-downloaded the latest version tonight. I'm still on the trial.
Also (maybe related?), when I click on consists, I often get notified of missing .bin files, even for pieces of rolling stock that I know I have and are working ok.
I feel like I'm likely missing something really obvious here, although not obvious enough that I've been able to figure it out!

EDIT: When I loaded up one of the scenarios I was trying to edit, the consist changes I tried to make had been made, but RW_Tools still shows the old consist...
Thanks