I'm sorry but there are some BGM errors. First at the house with yhe heart, people in the south part of the city, and the second event of the port, i see just now.
i tried exactly as you said but it still crashes midgame with the error "Unable to find file:Audio/BGS?[Japanese writing] 1 0 and a square" ....
Same here, exactly what i got. Which prevents entering the houses with a heart icon on top, and also cannot view the scene with two people doing it in public at the park either.
I have a feeling you didn't extract with Japanese encoding as described in that other commenter's explanation.
Open your "Gran Ende/Audio/BGM/" folder. Inside, you should see this (look at the filenames in kanji):
If you see this instead, you did something wrong (look at the filenames with garbled and random characters):
To fix it:
1. Download and install
You must be registered to see the links
2. Download the gran_ende.zip from the OP again (if you've already deleted it)
3. Right click the downloaded gran_ende.zip, click "Open with WinRAR"
4. After it opens, click the Options menu at the top and select "Name Encoding >> 932 (ANSI/OEM Japanese Shift-JIS)"
5. Drag the Gran Ende folder from the WinRAR window to your desktop (or whereever you want it saved)
6. Check the BGM folder (or any of the other folders for that matter) to verify that it shows kanji in the filenames as above
You will also likely need to run the game in Japanese Locale. If you don't know how to do that, see this post for more information:
https://f95zone.to/threads/how-to-run-japanese-games-on-windows.1040/
I use "HF pAppLoc" from that post, on Win7 64bit and it works great. After installing it, just right click the .exe of the game you want to play and select "Run with Japanese locale as administrator". Install this once and you won't ever have to worry about the "hassle" of Japanese locale games in the future, because 99% of the time AppLoc will work without issue. For the other 1% NTLEA seems to be more effective (again, see above post for more info on this). This is, of course, provided that you extracted the game correctly as described above.
Good luck.
(EDIT: Changed instructions to numbered list for better clarity, and corrected the locale emulators I use)