How to use ejaxupload extension?

I have a problem with EAJAXUPLOAD extension i followed the instructions from the yii site here but i always end up with a "failed" message.

does anyone know how to make this extension work? and i would also like to know where to put the upload folder.

action:


public function actionUpload()

	{

	        Yii::import("ext.EAjaxUpload.qqFileUploader");


                $folder='upload/';// folder for uploaded files

                $allowedExtensions = array("jpg");//array("jpg","jpeg","gif","exe","mov" and etc...

                $sizeLimit = 10 * 1024 * 1024;// maximum file size in bytes

                $uploader = new qqFileUploader($allowedExtensions, $sizeLimit);

                $result = $uploader->handleUpload($folder);

                $result=htmlspecialchars(json_encode($result), ENT_NOQUOTES);

                echo $result;// it's array

	}

view:


<? $this->widget('ext.EAjaxUpload.EAjaxUpload',

                 array(

                       'id'=>'uploadFile',

                       'config'=>array(

                                       'action'=>'/Site/upload',

                                       'allowedExtensions'=>array("jpg"),//array("jpg","jpeg","gif","exe","mov" and etc...

                                       'sizeLimit'=>10*1024*1024,// maximum file size in bytes

                                       'minSizeLimit'=>0*1024*1024,// minimum file size in bytes

                                       //'onComplete'=>"js:function(id, fileName, responseJSON){ alert(fileName); }",

                                       //'messages'=>array(

                                       //                  'typeError'=>"{file} has invalid extension. Only {extensions} are allowed.",

                                       //                  'sizeError'=>"{file} is too large, maximum file size is {sizeLimit}.",

                                       //                  'minSizeError'=>"{file} is too small, minimum file size is {minSizeLimit}.",

                                       //                  'emptyError'=>"{file} is empty, please select files again without it.",

                                       //                  'onLeave'=>"The files are being uploaded, if you leave now the upload will be cancelled."

                                       //                 ),

                                       //'showMessage'=>"js:function(message){ alert(message); }"

                                      )

                      )); ?>

i put the action code in controllers/SiteController.php and the view code in site/index.php