Extension with API

It says that I have no Infotable created...but this is exactly what I want to do with some kind of conversor...

Here is my code following what is in this link:

var text = '{ "employees" : [' +

'{ "firstName":"John" , "lastName":"Doe" },' +

'{ "firstName":"Anna" , "lastName":"Smith" },' +

'{ "firstName":"Peter" , "lastName":"Jones" } ]}';

var json = JSON.parse(text);

var params = {

infoTableName : "employees",

dataShapeName : "AlertEvent"

};

// CreateInfoTableFromDataShape(infoTableName:STRING("InfoTable"), dataShapeName:STRING):INFOTABLE(AlertEvent)

var result = Resources["InfoTableFunctions"].CreateInfoTableFromDataShape(params);

for(var i=0;i<json.length;i++){

    Infotable.AddRow({Name:json.firstName, Value:json.lastName});

    }

//}

result = InfoTable;