You need to have sigpatches enabled to make these work. There are several ways to do this, for example the
Simple Signature Patcher by Dimok. Just place it on the SD Card that resides in your Wii U and run the app from HBL. It looks like all it does is reload the Wii U menu, but this time signature patches will be enabled and you should be able to play the Wii titles from the eshop just fine. However, the Signature Patcher has to be run every time you turn on or restart the console, since it's patches are not permanent. If you want a permanent solution, I recommend taking a look at Coldboot HaxChi, for short CBHC. CBHC installs itself into a legit Nintendo DS Virtual Console title that has to be bought from the eshop, so yes you have to invest around 5-7 bucks for it, but for that CBHC can apply the signature patches in an automatic fashion each time you power on or restart your console. This also enables you to install the channel version of HBL, so you don't have to rely on the browser anymore to load homebrew apps. If you are interested, everything you need to know about CBHC can be found in this nice
FAQ written by Comm4nd_. To download and install CBHC visit the official thread found
here