Do you know why RockBox (on Sansa Clip+) allows only a few levels of driectiories? And the length of path doesn't matter, for example \a\a\a\a\a\a\a\a\a\a\ doesn't work, but "\dsfsdjfijsdigjdfgdfgdfgdfgdfgdfgdfgdfg\" works properly.
The situation descrived above takes place in building library, the song which has "to many" levels, are not available then in library.
Thanks in advance for help !