Ensure you have 00278.7z.001 , 00278.7z.002 , and any subsequent files in the same directory.
If one part was not downloaded completely, the extraction will fail. Re-downloading the specific broken part usually fixes this. Conclusion 00278.7z.002
This article breaks down exactly what 00278.7z.002 means, why files are split this way, and how to successfully extract the data within. What is a .7z.002 File? Ensure you have 00278