I tryed when v3.6 fixed is released and it works fine for me but only the name of the selected file is displayed and the documentation says (what I already knew):
[주의]
LFN으로 된 파일은 MSX-DOS2 커널에서 인식하지 못합니다.
해당 파일을 복사/삭제/이름변경 하면, FAT이 손상되므로,
읽기전용으로만 사용하세요!
[caution]
Files in LFN are not recognized by the MSX-DOS2 kernel.
If you copy/delete/rename the file, the FAT will be damaged.
Read-only use!
So it doesn't really matter. I would prefer the developer to take better account of particular cases to avoid crashes when an error or something unexpected happens.
When error handling will be more robust, M file manager will be a must.
I use the Sunrise CF with the latest nextor driver. As for your problem, check if your FAT is not damaged, And make sure the filenames don't have characters that only the Fontpack can display.
The v4.0 does not work under nextor?