CommandInvokationFailure: Android Asset Packaging Tool failed (No stderr to lookup)

I'm new to Android development but I've gotten far enough (drivers, unity external tools path, etc) to get to this error. As you can see below, the stderr isn't giving me anything to work with.

Some additional information:
Windows 7
Phone: VS985 4G LTE (LG G3)
Android Version: 4.4.2
Unity: 4.5.4f1

In the Android SDK Manager I have Tools (23.0.5), Platform-tools (21) and Build-tools (21) installed, along with the Android 4.4.2 (API 19).

From my unity editor log:

... (long list of other...

CommandInvokationFailure: Android Asset Packaging Tool failed (No stderr to lookup)