Commented Unassigned: ArgumentNullException was unhandled [132]

When I run the hello word program, I get the exception ArgumentNullException (see pic), How should I deal with it?
Comments: Your engine instance is null. Create CharacterVector is implemented as an extension method /// <summary> /// Creates a new empty CharacterVector with the specified length. /// </summary> /// <param name="engine">The engine.</param> /// <param name="length">The length.</param> /// <returns>The new vector.</returns> public static CharacterVector CreateCharacterVector(this REngine engine, int length) { if (engine == null) { throw new ArgumentNullException(); } if (!engine.IsRunning) { throw new ArgumentException(); } return new CharacterVector(engine, length); } I'm not sure if you are creating the engine instance somewhere else, but you should have a Get or Create instance call somewhere (depending on your version).