KOreader on Kobo Touch doesn't open an epub anymore...

Hi all,

some months ago I read a big book adding a lot of highlights and bookmarks.
Yesterday I tried to reopen it and... KOreader crashed, falling back to the Kobo Start Menu and it does the same every time I try. :bigcry:
The only way to reopen the ebook is to delete the sdr folder, but this is not a solution of course, since I would lose all the above mentioned highlights and bookmarks which are the reason why I need this book...
I already tried to let it create a new sdr folder and then overwrite the lua file: no success.
I also tried to edit the new empty lua file copying and pasting the highlights and bookmarks from the original one: no success.

Did it happen to someone else?
Do you have any solution/idea/suggestion?

:help:

Thanks in advance.