Hello everybody! I need your help!

I have a FormPanel in extjs 3.4 and I want to load data from seerver via a webservlet but I am a bit confused.

The webservlet responses with the following JSON information:
{"items":{"address":"1","email":"[email protected]","lastname":"aaa","firstname":"olia"},"success":true}

I tried two ways:
A. After layout.setActiveItem('FormPanellID'); I
I used:
FormPanel .getForm().load({ url: 'servletURL',
failure: function(form, action) {
Ext.Msg.alert("Load failed", action.result.errorMessage);
}
});

but I get the failed message!

B. I create a new Ext.data.JsonStore
var panelStore = new Ext.data.JsonStore({ autoLoad: true,
autoDestroy: true, url : 'servletURL',
root: 'items',
fields: [' 'email', 'firstname', 'address', 'status', 'lastname', ''],
listeners : {
load: function(store, records, options){
if(records[0]){
FormPanel.getForm().loadRecord(records[0]);
} else{
console.log("no data!");
}
}
}
});


and then I call panelStore .load();
but nothing happens!

I try 5 days to load data to a form but nothing! I thought that extjs was not too difficult
Could you please help me?