how do you judge that there are empty folders?
By looking into the folder-structure of new_opt.img?
If so, you are missing a big point of the linux file-system.
Linux file systems are mounted together at runtime from various sources.
For dictionaries this is the $dev$mtdblock11 (VFAT) which holds the physical data and holds a file SWNMTeb.ttc with some 10MB size.
You can dump this block with ebook_msc.exe from porkupan/borodas russification pack, and extract the content with a Disk-Image-Editor like WinImage.
On the other hand you should try to mount only a single font-file and not the whole font folder, thus leaving the link intact.