Funny actually as I have encountered similar problems when trying to run BrawlEX packs, from what I can tell unless it is hackless you will need a launcher of some kind (preferably the Project M launcher).
DIRECTIONS:
1) Download Project M (the homebrew version, link is here:
http://projectmgame.com/en/download) or if you have already look in the "projectm" folder and you should find a folder titled "launcher".
2) Copy that file into the spot where the "pf" folder of the hack pack you're trying to load (Not inside the "pf" folder, just where it is located) is located.
3) Next go back to your Project M rar and go into the "apps" folder and pluck out the "projectm" folder and put it in the "apps" folder of the hack pack.
4) Once you've done all of that move the files of your hack pack to the root of your SD card and then eject it from your computer.
5) Reinsert your SD card into your Wii and go to the Homebrew Channel, you should see the Project M Launcher icon, click on that and hit Play, it may take a little bit and it may crash occasionally (don't worry it happens) but it should load up the hack.
I Tried It It Just Loads The Game As If You Just Loaded It From The Disc Channel.