The AK::SoundEngine::LoadBank() method might return AK_Fail even if the low-level IO's base and language-specific paths have been properly set. This error's most common cause is that certain plug-ins have not properly been registered.
Indeed, if a game loads the initialization bank of a project that uses source or effect plug-ins, these plug-ins need to have been registered before the call to AK::SoundEngine::LoadBank(). The same is valid for codecs such as Vorbis.
Looking at the Capture Log while Wwise is connected to your game and the initialization bank is about to be loaded will highlight the source of the problem.
