@JerryRat I see 3 solutions, the file doesn't exist, it's in read-only mode or Spicetools don't have the right file paths.
Verfiy the prop folder, it comes with the game installation (its not generated by spicetools).
Start your apps with admin rights, all of them.
In Spicetools options menu you can manually specify the file path of avs-config.xml (scroll down it's argument is -v)
If you don't have it or its corrupted here's mine (it's IIDX 27 Heroic verse tho)
Also this is a sound voltex thread, there is a beatmania one already if you need more help.
avs-config.xml