Error: libAPPPurchase.a are required to have universal IOS libraries

An ANE has several parts, detailed in the 5-part tutorial I linked:

- a native library for each platform you're targeting (on iOS, this is a .a file)

- a SWC library that you use in your AS3 code to call functions in your ANE

- an optional default SWC library that has the full API but all the methods stubbed out for platforms you don't support so you can still compile for them.

The iOS part will be an XCode project, which you will them compile into a .a.  Then you package all the pieces up into an ANE using Adobe's command-line tools.  This last part is documented in part 5 of the tutorial I linked: Building a native extension for iOS and Android – Part 5: Building the ANE file | Adobe Developer Connection

First off, you'll need a Mac to install xcode and recompile the .a with 64-bit support.  You'll need the original source code.

You'll need to set the build architectures to support 64-bit by setting the Architectures setting to $(ARCHS_STANDARD) (this supports armv7 and arm64).

Here's a screenshot from one of my projects:

Then you'll need to re-package the ANE.

Here's a series of articles on ANE development in general that helped me: http://www.adobe.com/devnet/air/articles/building-ane-ios-android-pt1.html

Good luck!