Dear Rathnak,
Here is an alternative method to import demo data.
1. Extract the downloaded zip file, there will be 3 files with extension xml, wie and dat
2. Import xml file using WordPress Importer ( https://wordpress.org/plugins/wordpress-importer/ )
3. Import wie file using Widget Importer & Exporter ( https://wordpress.org/plugins/widget-importer-exporter/ )
4. Import dat file using Customizer Export/Import ( https://wordpress.org/plugins/customizer-export-import/ )
Regards!