Hi Commander Shepard,
For what platform are you packaging? If it is for Windows, you can’t target Win64 in shipping from the binary build. We only support Win64 for development builds, and only support Win32 for shipping. This is functionality that may be changed in a future release to allow for packaging for both via the binary build, but it is as yet unannounced.
Here’s some documentation related to general packaging, and here is the AnswerHub thread that addresses shipping builds for Win32.
Good luck!