The AppHelper project was deprecated in DevForce EF 4.3.0.1. It's no longer automatically generated by the Object Mapper, but is still supported at run time for those applications still using an AppHelper. In versions prior to 4.3.0.1, the AppHelper project held an app.config file as an embedded resource. This was done to provide a central location for configuration information. In version 4.3.0.1 and forward a standard, non-embedded, app.config file is now used, and generated into several projects.
If you're using a version of DevForce which uses the AppHelper, there's nothing you need to do. The Initializer.cs was automatically called by the framework during initialization, but you don't need to modify this class, or any other part of the project. DevForce specifically looks for an assembly named "AppHelper" when probing for configuration information at run time.