exactly what he saidI think what you need to do is you:
1. Lauch the game with the original files (no hotfix)
2. After lauching, replace the files in the location you installed the game with the hotfix. For example C:/Riot Games/League of Legends/Game.
3. After that inject the hack and it should work.
Remember to store the original LOL files and after the game, copy it back.
Always keep a copy of the original files and repeat the process when you close the game and want to open and play again.