Did you simply copy the file that was linked to in the wiki? or did you create a new one with the same content? if you created a new file, did you edit it in windows? If that’s the case, double check that you saved the file as a UNIX file, and not PC.
As long as the mouse.cfg file is in the right place (ie., the same path that’s called out in the edit you just made.) and is a UNIX file, then it should work.
One thing you might try is changing permissions on the mouse.cfg file.
Try running this:
sudo chmod +x /usr/local/mouse.cfg
That will ensure that the mouse.cfg file is executable.