NSException is thrown when there are rogue outlets mappings. You can check this out in the connection inspector.
I have downloaded the project and receiving the same NSException error. It looks like the project is missing some of the class files like Splash1ViewController, Splash2ViewController which are referred by the viewcontrollers in iphone.storyboard. The files are available under sample folder but not added as part of the Project. Not sure the about the reason for this..
I have managed to get this running by adding the missing files to sample folder. Constants.h, SplashViewController.h & .m, Splash2ViewController.h & .m , Splash3ViewController.h & .m
Also in MessagesTableViewController.m changed Constants.m to Constants.h.
Updated project can be downloaded from here - https://github.com/rshankras/solutions-mobile-backend-starter-ios-client
Hope this gives you some pointers to play around with the sample project.