Are you seeing any specific when you try to open the file?
If you are missing any parts (e.g., if you only have .003 ), the extraction will fail with a "Missing volume" or "Data error." Ensure you have the complete set from your source. SS-Nit-008_v.7z.003
The software will automatically detect and "stitch" all the parts together to give you the final file. Are you seeing any specific when you try to open the file