After that try running the game again and it might ask you to install again. Uninstall it completely from the 'add or remove programs' if it's in there, then delete the C:\Program Files\Blizzard\Bonjour Service and C:\Program Files (x86)\Blizzard\Bonjour Service. Due to that error message, I can assume Bonjour was already installed, but it's currently in a broken state either due to its service being disabled or an attempt at removing it.
