I have ran into an issue as the attached picture shows.
http://i.imgur.com/NapE94E.png
I have downloaded the Unreal 4.8 engine from Epic Games Github and the integration kit (Wwise 2015.1 - UE4.8 [2015-06] (Stable)) from audiokinetic. I then installed the engine by building it with Visual Studio 2013. I proceeded with extracting the Wwise integration files into the ue4 engine folder, and copying the correct files from my Wwise installation folder into the ue4 engine. As the Wwise Unreal integration documentation (Building the integration) states I should now rebuild (not build) the engine as it has already been built earlier. ("If it has already been built prior to importing the Wwise integration, it will need to be rebuilt from the existing UE4.sln before running UE4\GenerateProjectFiles.bat.")
I've tried searching for a solution but I've found none, admitting I might be bad at Visual Studio and/or googling.