While importing a survey archive, the process fails while importing the responses with

XMLReader::open(): Unable to open source data
on :
/var/www/html/application/helpers/admin/import_helper.php(2116)

2104 @param string $sFullFilePath
2105 @return mixed
2106 */
2107 function XMLImportResponses($sFullFilePath, $iSurveyID, $aFieldReMap = array())
2108 {
2109 Yii::app()->loadHelper('database');
2110 $survey = Survey::model()->findByPk($iSurveyID);
2111
2112 switchMSSQLIdentityInsert('survey_'.$iSurveyID, true);
2113 $results = [];
2114 $results['responses'] = 0;
2115 $oXMLReader = new XMLReader();
2116 $oXMLReader->open($sFullFilePath);