Suitescript 2 - Create Form INSUFFICIENT PERMISSION error

Hi, I'm trying to create a Before Load script to create a subtab for the Sales Order Form and insert a sublist with the result of a Search.

I'm working on administrator Role

i have defined the serverWidget , but when reach the li

      var form = serverWidget.createForm({ title: 'Hello World Suitelet' });

it gives me the error

{"type":"error.SuiteScriptError","name":"INSUFFICIENT_PERMISSION","message":"You do not have privileges to perform this operation","stack":["createError(N/error)","beforeLoad(/SuiteScripts/[SSF]AggPrezzoScript.js:36)"],"cause":{"type":"internal error","code":"INSUFFICIENT_PERMISSION","details":"You do not have privileges to perform this operation","userEvent":"beforeload","stackTrace":["createError(N/error)","beforeLoad(/SuiteScripts/[SSF]AggPrezzoScript.js:36)"],"notifyOff":false},"id":"","notifyOff":false,"userFacing":false}