FWIW, here's what my directory structure looks like, and, last I checked, that was working fine

.
Code:
/mnt/onboard/.adds/koreader/data/dict/etymonline/:
total 6008
4 drwxr-xr-x 2 root root 4.0K May 28 01:01 .
4 drwxr-xr-x 5 root root 4.0K Sep 14 08:33 ..
5052 -rwxr-xr-x 1 root root 4.9M May 28 01:00 stardict.dict.dz
776 -rwxr-xr-x 1 root root 772.4K May 28 01:00 stardict.idx
8 -rwxr-xr-x 1 root root 5.7K May 28 01:01 stardict.idx.oft
4 -rwxr-xr-x 1 root root 182 May 28 01:00 stardict.ifo
160 -rwxr-xr-x 1 root root 157.4K May 28 01:00 stardict.syn
/mnt/onboard/.adds/koreader/data/dict/gcide/:
total 15660
4 drwxr-xr-x 2 root root 4.0K May 2 2018 .
4 drwxr-xr-x 5 root root 4.0K Sep 14 08:33 ..
13576 -rwxr-xr-x 1 root root 13.3M May 2 2018 stardict.dict.dz
1888 -rwxr-xr-x 1 root root 1.8M May 2 2018 stardict.idx
16 -rwxr-xr-x 1 root root 13.2K May 2 2018 stardict.idx.oft
4 -rwxr-xr-x 1 root root 177 May 2 2018 stardict.ifo
168 -rwxr-xr-x 1 root root 166.1K May 2 2018 stardict.syn
/mnt/onboard/.adds/koreader/data/dict/xmlittre/:
total 34576
4 drwxr-xr-x 2 root root 4.0K May 2 2018 .
4 drwxr-xr-x 5 root root 4.0K Sep 14 08:33 ..
32272 -rwxr-xr-x 1 root root 31.5M May 2 2018 stardict.dict.dz
1496 -rwxr-xr-x 1 root root 1.5M May 2 2018 stardict.idx
12 -rwxr-xr-x 1 root root 9.6K May 2 2018 stardict.idx.oft
4 -rwxr-xr-x 1 root root 146 May 2 2018 stardict.ifo
784 -rwxr-xr-x 1 root root 782.0K May 2 2018 stardict.syn