Oceania OSX install isn’t working after download

Hi so I have a MACBOOK PRO,

I downloaded League of legends Oceania OSX today, so I could reinstall, after recently uninstalling because of a bug. Anyway, when I tried to use the install package I had downloaded, it doesn’t work. I click on the application, after I have moved it into my applications folder, and nothing will happen. It looks like it is loading for like a second, then it just exits into nothing, and nothing happens. I have tried restarting computer, rebooting computer, double checked that all LOL software has been removed prior to downloading again. Everytime though, I encounter the same problem, and I have downloaded the installer about 10 different times today, same result everytime. It doesnt work.

Has anyone had this problem before? does anyone know the solution?