The error only occurred in this game and in the part where it extracts the RPA files. I was even able to extract the RPyC files without problems. I didn't have this error in other games; it was exclusive to this one, which is cataloged as version 8.5.0.
In practice, this means:
The program is looking for a file inside the .rpa archive, but
the filename it's looking for is empty ('').
Because the filename is empty or invalid, the archive can't find it and returns the error Errno 2 (file does not exist).
Why does this happen?
This error usually occurs when:
A mod, translation patch, or extracted file is corrupted or incomplete.
The program reading the .rpa archive received an incorrect path, or a line of code requests an unnamed file.
The .rpa archive has been modified, corrupted, or does not match the game version.