AIR 15.0 for OSX - ADT: Packaging failed. Packager internal error

Packaging a SWF to AIR with captive runtime and native installer (using "-package bundle"), building on PC worked perfectly fine.  After making all of the requisite changes to make it work for Mac, I'm now running into the "Packaging failed. Packager internal error" when building using adt through the command line.  My .command script is as follows:

cd [directory]

adt -package -storetype pkcs12 -keystore ../cert/key.p12 -storepass pw -target bundle Bundle ../App.xml App.swf -extdir ../lib icons/16.png icons/32.png icons/128.png

What can cause this vague "Packger interal error" error? Any help would be appreciated. Thank you.