Android - Titanium error , pressed back native android

When I press the emulator loops back the following exception.

[ERROR] : [Nexus 5] TiApplication: (main) [18937,27197] Sending event: exception on thread: main msg:java.lang.NullPointerException; Titanium 3.3.0,2014/07/11 12:36,787cd39 [ERROR] : [Nexus 5] TiApplication: java.lang.NullPointerException [ERROR] : [Nexus 5] TiApplication: at android.widget.Toast.<init>(Toast.java:93) [ERROR] : [Nexus 5] TiApplication: at android.widget.Toast.makeText(Toast.java:241) [ERROR] : [Nexus 5] TiApplication: at ti.modules.titanium.ui.widget.TiUINotification.<init>(TiUINotification.java:27) [ERROR] : [Nexus 5] TiApplication: at ti.modules.titanium.ui.NotificationProxy.createView(NotificationProxy.java:34) [ERROR] : [Nexus 5] TiApplication: at org.appcelerator.titanium.proxy.TiViewProxy.handleGetView(TiViewProxy.java:483) [ERROR] : [Nexus 5] TiApplication: at org.appcelerator.titanium.proxy.TiViewProxy.getOrCreateView(TiViewProxy.java:469) [ERROR] : [Nexus 5] TiApplication: at ti.modules.titanium.ui.NotificationProxy.handleShow(NotificationProxy.java:41) [ERROR] : [Nexus 5] TiApplication: at org.appcelerator.titanium.proxy.TiViewProxy.handleMessage(TiViewProxy.java:253) [ERROR] : [Nexus 5] TiApplication: at android.os.Handler.dispatchMessage(Handler.java:98) [ERROR] : [Nexus 5] TiApplication: at android.os.Looper.loop(Looper.java:136) [ERROR] : [Nexus 5] TiApplication: at android.app.ActivityThread.main(ActivityThread.java:5001) [ERROR] : [Nexus 5] TiApplication: at java.lang.reflect.Method.invokeNative(Native Method) [ERROR] : [Nexus 5] TiApplication: at java.lang.reflect.Method.invoke(Method.java:515) [ERROR] : [Nexus 5] TiApplication: at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:785) [ERROR] : [Nexus 5] TiApplication: at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:601) [ERROR] : [Nexus 5] TiApplication: at dalvik.system.NativeStart.main(Native Method)

or

picker null exeption

code picker

`$.login.addEventListener('open', function(evt) {

    try
    {
        acaoSelecao($.picker.getSelectedRow(0).val);        
        $.usuario.addEventListener('blur', mascaraCampoLogin);  
        $.login.orientationModes = [Ti.UI.PORTRAIT];        
    }
    catch (e) {
        alert(JSON.stringify(e.message));
    }


});

try { $.login.addEventListener('android:back', function (e) {

    $.login.close();


});

} catch (e) { alert(JSON.stringify(e.message)); }

function mascaraCampoLogin() { var mask = new Mask(); var opcao = $.picker.getSelectedRow(0).val; var customDialog = new CustomDialog(); var usuario = $.usuario.value;

        switch(opcao)
        {
            case 'RegistroCidadao': 

                $.usuario.keyboardType = Titanium.UI.KEYBOARD_NUMBER_PAD;

                var qtd = (10 - usuario.length);


                if(usuario.length < 3) {
                    customDialog.toast("Registro cidadão incorreto.");
                }
                else {

                    var usuarioAntigo = usuario;
                    var novoUsuario = "";

                    for (var i=0; i < qtd; i++) {
                        novoUsuario += 0;
                    };

                    novoUsuario += usuarioAntigo;

                    if((novoUsuario.length > 10) && !(validaRegistroCidadao(novoUsuario).length == 10)) {                        
                        customDialog.toast("Registro cidadão incorreto.");
                    }
                    else {
                        $.usuario.value =  mask.cartaoCidadao(novoUsuario);
                    }

                }

                // Limpa o campo se usuário for igual a 0000000
                if($.usuario.value == "00000000-00") {
                    $.usuario.value = "";
                }

                break;
            case 'NumeroCartaoSus':
                $.usuario.keyboardType = Titanium.UI.KEYBOARD_NUMBER_PAD;

                if(usuario.length != 15) {
                    customDialog.toast("Cartão Sus incorreto.");
                }

                break;
            case 'FoneCelular1':
                $.usuario.keyboardType = Titanium.UI.KEYBOARD_NUMBER_PAD;

                if(usuario.length == 10 || usuario.length == 11) {                      
                    $.usuario.value =  mask.telefone($.usuario.value);
                }
                else {
                    customDialog.toast("Telefone incorreto.");
                }


                break;
            case 'EmailCidadao':
                $.usuario.keyboardType = Titanium.UI.KEYBOARD_EMAIL;

                if(!validaEmail(usuario)){
                    customDialog.toast('Por favor, digite o email corretamente');
                }

                break;
            case 'NumeroCpf':
                $.usuario.keyboardType = Titanium.UI.KEYBOARD_NUMBER_PAD;

                if(!validaCPF(usuario)) {
                    customDialog.toast("Cpf incorreto.");
                }
                else {
                    $.usuario.value =  mask.cpf($.usuario.value);           
                }

                break;  
        }   

}`