I was following along until this... There is no Omnifocus Scripts Folder when I do an Open Scripts Folder on my system.
Do I need to create the folder first? If so, where? In user scripts or computer scripts?
If you are in OmniFocus as the frontmost application (menu bar will say OmniFocus, not Finder or Safari or whatever), then when you do the Open Scripts Folder from the Scripts menu, it will create that folder for you automatically if it did not exist.