ios-driver response arguments to waitForElementByCss

response.js

{ '0': null,
  '1':
   { message: 'bug.null\nBuild info: version: \'unknown\', revision: \'unknown\', time: \'unknown\'\nSystem info: os.name: \'Mac OS X\', os.arch: \'x86_64\', os.version: \'10.9.2\', java.version: \'1.7.0_21\'\nDriver info: driver.version: unknown',
     screen: null,
     cause:
      { screen: null,
        class: 'java.lang.NullPointerException',
        stackTrace: [Object] },
     class: 'org.openqa.selenium.WebDriverException',
     stackTrace:
      [ 
        { fileName: 'FindElementsHandler.java',
          lineNumber: 61,
          className: 'org.uiautomation.ios.server.command.web.FindElementsHandler',
          methodName: 'handle' },
       { fileName: 'BaseCommandHandler.java',
         lineNumber: 104,
         className: 'org.uiautomation.ios.server.command.BaseCommandHandler',
         methodName: 'handleAndRunDecorators' },
       { fileName: 'IOSServlet.java',
         lineNumber: 137,
         className: 'org.uiautomation.ios.server.servlet.IOSServlet',
         methodName: 'getResponse' },
       { fileName: 'IOSServlet.java',
         lineNumber: 81,
         className: 'org.uiautomation.ios.server.servlet.IOSServlet',
         methodName: 'process' },
       { fileName: 'IOSServlet.java',
         lineNumber: 56,
         className: 'org.uiautomation.ios.server.servlet.IOSServlet',
         methodName: 'doPost' },
       { fileName: 'HttpServlet.java',
         lineNumber: 727,
         className: 'javax.servlet.http.HttpServlet',
         methodName: 'service' },
       { fileName: 'HttpServlet.java',
         lineNumber: 820,
         className: 'javax.servlet.http.HttpServlet',
         methodName: 'service' },
       { fileName: 'ServletHolder.java',
         lineNumber: 533,
         className: 'org.eclipse.jetty.servlet.ServletHolder',
         methodName: 'handle' },
       { fileName: 'ServletHandler.java',
         lineNumber: 475,
         className: 'org.eclipse.jetty.servlet.ServletHandler',
         methodName: 'doHandle' },
       { fileName: 'SessionHandler.java',
         lineNumber: 224,
         className: 'org.eclipse.jetty.server.session.SessionHandler',
         methodName: 'doHandle' },
       { fileName: 'ContextHandler.java',
         lineNumber: 920,
         className: 'org.eclipse.jetty.server.handler.ContextHandler',
         methodName: 'doHandle' },
       { fileName: 'ServletHandler.java',
         lineNumber: 403,
         className: 'org.eclipse.jetty.servlet.ServletHandler',
         methodName: 'doScope' },
       { fileName: 'SessionHandler.java',
         lineNumber: 184,
         className: 'org.eclipse.jetty.server.session.SessionHandler',
         methodName: 'doScope' },
       { fileName: 'ContextHandler.java',
         lineNumber: 856,
         className: 'org.eclipse.jetty.server.handler.ContextHandler',
         methodName: 'doScope' },
       { fileName: 'ScopedHandler.java',
         lineNumber: 117,
         className: 'org.eclipse.jetty.server.handler.ScopedHandler',
         methodName: 'handle' },
       { fileName: 'HandlerList.java',
         lineNumber: 47,
         className: 'org.eclipse.jetty.server.handler.HandlerList',
         methodName: 'handle' },
       { fileName: 'HandlerWrapper.java',
         lineNumber: 114,
         className: 'org.eclipse.jetty.server.handler.HandlerWrapper',
         methodName: 'handle' },
       { fileName: 'Server.java',
         lineNumber: 352,
         className: 'org.eclipse.jetty.server.Server',
         methodName: 'handle' },
       { fileName: 'HttpConnection.java',
         lineNumber: 596,
         className: 'org.eclipse.jetty.server.HttpConnection',
         methodName: 'handleRequest' },
       { fileName: 'HttpConnection.java',
         lineNumber: 1066,
         className: 'org.eclipse.jetty.server.HttpConnection$RequestHandler',
         methodName: 'content' },
       { fileName: 'HttpParser.java',
         lineNumber: 805,
         className: 'org.eclipse.jetty.http.HttpParser',
         methodName: 'parseNext' },
       { fileName: 'HttpParser.java',
         lineNumber: 212,
         className: 'org.eclipse.jetty.http.HttpParser',
         methodName: 'parseAvailable' },
       { fileName: 'HttpConnection.java',
         lineNumber: 426,
         className: 'org.eclipse.jetty.server.HttpConnection',
         methodName: 'handle' },
       { fileName: 'SelectChannelEndPoint.java',
         lineNumber: 510,
         className: 'org.eclipse.jetty.io.nio.SelectChannelEndPoint',
         methodName: 'handle' },
       { fileName: 'SelectChannelEndPoint.java',
         lineNumber: 34,
         className: 'org.eclipse.jetty.io.nio.SelectChannelEndPoint',
         methodName: 'access$000' },
       { fileName: 'SelectChannelEndPoint.java',
         lineNumber: 40,
         className: 'org.eclipse.jetty.io.nio.SelectChannelEndPoint$1',
         methodName: 'run' },
       { fileName: 'QueuedThreadPool.java',
         lineNumber: 450,
         className: 'org.eclipse.jetty.util.thread.QueuedThreadPool$2',
         methodName: 'run' },
       { fileName: 'Thread.java',
         lineNumber: 722,
         className: 'java.lang.Thread',
         methodName: 'run' } 
      ] 
    } 
  }

step_definition

  this.Then(/^I should be redirected to (.*)$/, function (url, callback) {
    this.device
      .waitForElementByCssSelector('body.util-fill', asserters.isDisplayed, 10000)
        .should.eventually.be.ok
      .then(function() {
        callback();
      }, callback);
  });

can you share the page you're testing ?