Remove the lib\gimp\2.0\plug-ins\file-png.exe file and save it somewhere else like your desktop.
Place the two files  - "file-apng.exe AND file-apng.ui in your lib\gimp\2.0\plug-ins folder
Place the intl.dll file in your gimp version\bin folder
RESTART GIMP
Create a doc with 4 layers  - 
1 bg all black
3 layers all transparent with a circle of different colors in the same location on the layers.
Go to File>EXPORT
Export as a png-apng image (drop down save as menu bottom left of the save as dialog window)
Choose animation in the next dialog window.
Now close the image NOT Gimp
Now go to File>Open open your saved APNG animation as a "png-apng image" the same drop down menu.
The image SHOULD open in layers.

the end  :)