TypeInitializationException thrown for Program class

Another possible reason: the app.config has duplicate sections.

So: either one of the field-initializers, or the static constructor, for Program - is failing. Find out why. Note: the InnerException has the actual exception that was raised, but basicaly: just debug the field initializers and static constructor. So look inside the Program class for either:

static SomeType someField = /* some non-trivial expression or method call */ 

or:

static Program() {
    // stuff
}