Tačke Od Interesa. Now clear?
Do not mix files. You have lang files that are intended for clear NG (first download links in OP), and langs adapted only for Pongo skin.
Also, you tried to change what? And where?
Every change in the zip file requires that it be done in the correct manner. Strictly.
By the way, the author of these files (not uploader) does not fulfill the music wishes. Respect his work & use them, or modify them by yourself.