title: Google Apps Script Cannot find method createFile((class))
body: <p>I just started scripting my first Google App and i can't seem to get pass this error.
  What my script does is that it creates a form that allows users to enter data into a google spreadsheet.
  And upload a file into the folder BIO.
  Please help me out!
  This is the code.</p>
  
  <pre><code>function doGet(e) {
    var app = UiApp.createApplication().setTitle('New app');
   var doc = SpreadsheetApp.openById('0AvOeZM3IzF-GdDRyV3NiTjBreC1ONXh0cHdDMlFhRGc');
    var grid = app.createGrid(5, 2);
    grid.setWidget(0, 0, app.createLabel('Code:'));
    grid.setWidget(0, 1, app.createTextBox().setName('codeName'));
    grid.setWidget(1, 0, app.createLabel('Uploaded Date'));
    grid.setWidget(1, 1, app.createTextBox().setName('date'));
    grid.setWidget(2, 0, app.createLabel("maid's Name"));
    grid.setWidget(2, 1, app.createTextBox().setName('maidName'));
  
  //creates vertical panel and declare as panel
    var panel = app.createVerticalPanel();
    panel.add(grid);
  
  
    var form = app.createFormPanel().setId('frm').setEncoding('multipart/form-data');
     panel.add(app.createFileUpload().setName('thefile'));
    form.add(panel);
  
  //creates submit button and declare as button
    var button = app.createButton('submit');
  
  //notsure
    var handler = app.createServerHandler('b');
  
  //notsure
    handler.addCallbackElement(grid);
  
  //notsure
    button.addClickHandler(handler);
  
  //add submit button to panel.
    panel.add(button);
  
  //addpanel to application
    app.add(panel);
  
  //display application
  
  
    app.add(form);
  
    return app;
  }
  
  function b(e) {
  
   var doc = SpreadsheetApp.openById('0AvOeZM3IzF-GdDRyV3NiTjBreC1ONXh0cHdDMlFhRGc');
   var lastRow = doc.getLastRow(); //Find the last row
   var cell = doc.getRange('a1').offset(lastRow, 0); //finds the next empty cell in column A
  
  cell.setValue(e.parameter.codeName);//i can access paremeter codeName because i setname('codeName') just now.
  cell.offset(0, 1).setValue(e.parameter.date);
  cell.offset(0, 2).setValue(e.parameter.maidName);
  
    var Blob = e.parameter.thefile;
    var folder = DocsList.getFolder('BIO');
    folder.createFile(Blob);
  
  
  
  var app = UiApp.getActiveApplication(); 
    var label = app.createLabel('File Upload Sucess')
    app.close(); //close widget
    return app; //close widget
  
  
  }
  </code></pre>
  
  <p>Thank you guys in advance!<br>
  Jasper.</p>