How do you mean that the things it said to try didn't work?
Do you mean that you managed to do them, but it did not make a difference, or, do you mean that you were unable to do them?
Here are some general Mac tips that are also in the manual:
1. If you unzip the file on a Windows machine and transfer the file to your mac with a USB stick it should work.
2. Better solution for anybody else who has this problem. OS X is picky about which programs can be run (the first time) by double-clicking. To run a program that says "this can't be opened", right-click the icon and choose "Open". You'll be given an option to open the program, and from then on it won't bug you.
3. For Mac's having trouble installing FPV Freerider try going to the Mac's System Preferences>Security and Privacy> General Tab and check the box "Anywhere" to see if this allows your Mac to install FPV Freerider.
4. So i have banging my head with frustration about not being able to even open the program in OSX 10.10. I have finally solved the problem for anybody who is still having the same issue i was, you have to open up terminal and type chmode +x (fpvfreerider.app) and that should do it. Hope this helps anybody.