Howdy SamIsewall,
Thank you for reporting your error. I am going to need a bit more information before I begin looking into this issue. What version of UE4 would you be using and is that version a binary build or source build of the engine? Would you be able to replicate this issue on a blank template project? Have you been able to package in any previous versions of UE4?
Any additional information would be greatly appreciated.
Thanks and have a great day!