I found the B4i Libraries folder and put it in there.
That's not the good way!
If you set the AdditionalLibraries folder as C:\AdditionalLibraries with the subfolders as explained in post #3 then set the AdditionalLibraries folder in the IDE as C:\AdditionalLibraries.
The IDE will automatically use the correct subfolder.
If you currently have an AdditionalLibraries folder for B4i, then move all files to C:\AdditionalLibraries\B4i.
The drawback with your solution is that the b4xlib will only be seen by B4i and not from B4A and B4J.