JQuery autocomplete can't get data from response in IE8

JQuery autocomplete can't get data from response in IE8

I have autocomplete on one textbox. it's working in IE9, firefox, chrome. but not working in IE8. error msg is :SCRIPT5007: Unable to get value of the property 'question': object is null or undefined. please read the following code and comments inside. Thanks.

  		1.
     

    1. $

       (function () { $newTFQ.find(

      "input[id$=tbQuestion]" ).autocomplete({

      source:

      function (request, response) {

      $.ajax({

      url:

      "Services/Questions.ashx" ,

      dataType:

      "jsonp" ,

      async:

      false ,

      data: {

      featureClass:

      "P" ,

      style:

      "full" ,

      type:

      "tf" ,

      maxRows: 10,

      name_startsWith: request.term

      },

      success:

      function (data) {

      response($.map(data.questions,

       

      function (q) {

      return {

      value:q.question,

      answer:q.answer,

      opta: q.opta,

      optb: q.optb,

      optc: q.optc,

      optd: q.optd

      }

      }))

      }

      })

      },

      minLength: 4,

      delay: 800,

      focus:

      function (event, ui) {

      return false ;

      },

      select:

      function (event, ui) {

      $(

      this ).val(htmlDecodeString20(ui.item.value));

      if (ui.item.answer == "1" )

      $newTFQ.find(

      '.answertf' ).find( 'input[value="1"]' ).prop( "checked" , true );

      else if (ui.item.answer == "0" )

      $newTFQ.find(

      '.answertf' ).find( 'input[value="0"]' ).prop( "checked" , true );

      $newTFQ.find(

      "input[name='" + tempstring1 + "'][value='1']" ).prop( "checked" , true );

      $newTFQ.find(

      "input[name='" + tempstring3 + "'][value='0']" ).prop( "checked" , true );

      return false ;

      }

      });

      });