You did everything right, I don't know. Did you try more than once or just once? If just once, retry it.
Actually try this if you didn't already.
Run Haxchi (I'm assuming you don't have coldboot haxchi)
Run Homebrew Launcher
Run WUP Installer GX and retry it.
I have no idea about that particular game so maybe it requires sig patches and running Haxchi would give you that.
If all of that fails I have no clue, try another game maybe because you're doing the basics correctly.
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It's been awhile since I've installed a game on Wii U I forgot you're probably using Haxchi to get to homebrew launcher automatically. If you are running Haxchi already I'm not sure your problem unless the disc has a scratch or something. I'd try another game.