failed to open stream: No such file or directory:file_put_contents

Question

i am trying to upload image and i get this error this is the error i get i dont have any idea what to do

1. i try to change 'src' but the picture cant upload.

2. i try to change file_put_contents but this is doesn't work.

   static function updateUserImage() {

       global $root;
       $file = reset($_FILES);
       $fileType = strtolower($file['type']);
       $allowedExt = ajaxParams('allowedExt');
       if (key_exists($fileType, $allowedExt) && file_exists($file['tmp_name'])) {
   
           $fileData = @file_get_contents($file['tmp_name']);
           $height = intval(trim(str_ireplace('px', '', ajaxParams('picHeight'))));
           $width = intval(trim(str_ireplace('px', '', ajaxParams('picWidth'))));
           $md5 = md5($fileData);
           $fileName = 'cache/cstFiles/' . $md5 . '.' . $allowedExt[$fileType];       
           file_put_contents($root.$fileName,$fileData);
   
           if ($height > 0 && $width > 0) {
               $params[crpFileType] = $allowedExt[$fileType];
               $params[crpDestinationDir] = $root . 'cache/cstFiles/';
               $params[crpOverwriteOrig] = true;
               $params[crpResizeMethod] = 'resize';
               $resizedPic = copyResizedPic2($root . $fileName, $width, $height, $params);
           }
   
       $key = time() . rand();
       $_SESSION[__mypAjaxSessionKey__]['mypc_file'][$key] = $fileName;
       return '
           <img src="' . $fileName . '"/>
           <input hidden type="text" name="' . ajaxParams('inputName') . '" value="' . $key . '"/>';
   }  }