I tried renaming the .zip file back to .ap but that won't fix it, it's still a ZIP archive. I tried installing the AP 159 pack again but it installs it to the main Class159 folder NOT the .ap (which is a zip archive) file.
I deleted the whole thing, uninstalled the 159 pack and re-installed it, best thing to do really. Installed the pack again and everything is all working fine and files successfully transferred
