Why does Engine Keep Crashing On Builds?

I am having some issues with the Game Engine closing down or exiting every time I try to build my project. My project contains three separate Persistent levels and landmass is single not tiled or such. I get no error messages, so that is not helpful to any one. Only way I am able to build the project is by opening each level one at a time to build it. Any one have any idea how to solve this issue? What may I be missing here that may be of help? What may I be missing on the other separate levels I need to add? I would like to simply load every level at one time to build the project if it is possible. Thanks for your time and help.