in this code
setting name is theme_options
please help me to solve it

piklist('field',array(
  'type'=>'group',
  'field'=>'books',
  'label'=>'Books Collection',
  'fields'=>array(
    array(
      'type'=>'checkbox',
      'field'=>'current_books',
      'label'=>'Select the current book',
      'choices'=>
          array(
          'js'=>'Javascritpt',
          'php'=>'PHP'
          )
    ),
    array(
      'type'=>'text',
      'field'=>'js',
      'label'=>'Enter the js book',
      'conditions'=>array(
        array(
          'field'=>' books:current_books',
          'value'=>'js'
        )
    )
    )
  )
));