[Alaa]

Hi,
I get an error when adding any books to my library.
The books are fine as I can open them with EPUBReader in Firefox.

Below is the error log.
Can anyone help?

calibre, version 4.10.1
ERROR: Errors while adding: Failed to add any books, click "Show details" for more information


----------------------------------------------------------------------
Failed to add the book: I, Alex Cross
V:\Books\Calibre (my books)\James Patterson\I, Alex Cross (245)\I, Alex Cross - James Patterson.epub
With error:
Traceback (most recent call last):
File "site-packages\calibre\gui2\add.py", line 414, in add_book
File "site-packages\calibre\db\legacy.py", line 225, in create_book_entry
File "site-packages\calibre\db\cache.py", line 62, in call_func_with_lock
File "site-packages\calibre\db\cache.py", line 1590, in create_book_entry
File "site-packages\calibre\db\cache.py", line 1310, in set_metadata
File "site-packages\calibre\db\cache.py", line 1136, in update_path
File "site-packages\calibre\db\backend.py", line 1606, in update_path
File "site-packages\calibre\db\tables.py", line 137, in set_path
File "site-packages\calibre\db\backend.py", line 874, in execute
File "c:\t\t\apsw-cjr7a2yu\src\cursor.c", line 236, in resetcursor
CantOpenError: CantOpenError: unable to open database file