Are you using the Homebrew Launcher.cia? My first guess would be that it wont open due to it having a older payload. But if you are connected to the internet it should just download the payload for you.
I updated all my emunand to the most current firmware, and it worked like a charm. I'm guessing it updated the payload upon starting the app.
Edit: If you are using a game to open HBL, you might need to update the payload manually. I.e run the installer for said hax again. All tho, that might be hard if it was your only entry to HBL.