plupload Codeigniter file upload issue-IO error 2032

i am using plupload script with codeigniter to upload files.I included all required files to make it work but now the issue is if i am trying to upload a image file large than 20 Kb than it will uploaded to the specific folder successfully but if you go and check the image file than only around 25% part of the image is visible other part is shown as a grey color.

and sometimes plupload shows IO error 2032 also.

I check my max post size and file upload size both are large enough to upload a 20 kb image file.

my script is:

    <script type="text/javascript">
 // Convert divs to queue widgets when the DOM is ready
 $(function() {
     var cct = $.cookie("<?php echo $this->config->item("csrf_cookie_name"); ?>");
     $("#uploader").pluploadQueue({
         // General settings
         runtimes : 'gears,flash,silverlight,browserplus,html5',
         url : '<?php echo base_url();?>index.php/uploadphoto',
         max_file_size : '5mb',
         chunk_size : '1mb',
         unique_names : true,
         multipart:true,
         multipart_params:{'<?php echo $this->security->get_csrf_token_name(); ?>': cct},
 
 
         // Specify what files to browse for
         filters : [
             {title : "Image files", extensions : "jpg,gif,png,bmp,jpeg"}
         ],
 
         // Flash settings
         flash_swf_url : '<?php echo base_url();?>js/plupload.flash.swf',
 
         // Silverlight settings
         silverlight_xap_url : '<?php echo base_url();?>js/plupload.silverlight.xap'
     });
 
 });
 </script>
 

and my controller upload photo is like this:

    $upload_path_url = './uploads/';
 
 
 
     $config['upload_path'] =$upload_path_url;
     $config['allowed_types'] = 'gif|jpg|png|bmp|jpeg';
     $config['max_size'] = '5500';
 
     $this->load->library('upload', $config);
     if ( ! $this->upload->do_upload('file'))
     {
         $error = array('error' => $this->upload->display_errors());
         //$this->load->view('upload', $error);
     }
     else
     {       
        $data = $this->upload->data();
     }
 

so give me any suggestion to solve this issue.

-Thanks in advance

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