Ok, I see what’s happening . It’s come to light recently that the plug-in version of iTween has cooking issues, as do many binary unreal plugins for now, unfortunately. This is why there’s a big red warning about using the plug-in version on the first page. I’ll have to put a warning in the installer when the user tries to install the plug-in version just to be sure. However, there are some things you can try.
First you can try launching the game using a version of the editor built from the source code. Download the code from github and build the engine, then cook the game again. Some people have had success with this when building with the plug-in version of iTween.
Alternatively you can uninstall the plug-in version and install the c++ version. You’ll still be able to use blueprints, business as usual, but you’ll have to build your game with the added c++ code. Keep in mind that in doing so, you won’t be able to cook for iPhone from Windows anymore. Code projects can only cook for ios from a mac computer. If you’re not building for iPhone or not using Windows, that’s not a concern 
you’ll also need to replace your itween nodes in your project since the plug-in nodes and c+±based nodes are incompatible. I know, it’s a pain but it’s unavoidable.
Failing either of those, you can just wait for Epic to fix this plug-in problem. It’s been plaguing plugins creators forever and there’s finally hope on the horizon for 4.8, but no clear guarantee. This is part of the reason you don’t see c++ code plugins on the marketplace - issues still exist.
I’m sorry that this is happening to you. I’ll have to go a little further to make sure people know the ramifications of using the plug-in version of iTween so we can avoid anyone else getting stuck .