Error al ejecutar .jar

[nicoguevara]

Hola, gracias por tu respuesta, no es el MAINFEST ya que si elegi la clase principal, me da el error al cargar la imagen creo.
Te pego lo que me sale cuando trato de correr desde cmd:


C:\Users\nguevara\workspace>java -jar optica.jar
java.lang.NullPointerException
at javax.swing.ImageIcon.<init>(Unknown Source)
at vista.Usuarios.<init>(Usuarios.java:162)
at vista.Usuarios$1.run(Usuarios.java:54)
at java.awt.event.InvocationEvent.dispatch(Unknown Source)
at java.awt.EventQueue.dispatchEventImpl(Unknown Source)
at java.awt.EventQueue.access$200(Unknown Source)
at java.awt.EventQueue$3.run(Unknown Source)
at java.awt.EventQueue$3.run(Unknown Source)
at java.security.AccessController.doPrivileged(Native Method)
at java.security.ProtectionDomain$1.doIntersectionPri vilege(Unknown Sour
ce)
at java.awt.EventQueue.dispatchEvent(Unknown Source)
at java.awt.EventDispatchThread.pumpOneEventForFilter s(Unknown Source)
at java.awt.EventDispatchThread.pumpEventsForFilter(U nknown Source)
at java.awt.EventDispatchThread.pumpEventsForHierarch y(Unknown Source)
at java.awt.EventDispatchThread.pumpEvents(Unknown Source)
at java.awt.EventDispatchThread.pumpEvents(Unknown Source)
at java.awt.EventDispatchThread.run(Unknown Source)