jak w temacie, gdy próbuję zapisać powiedzmy 30 ebooków na dysk w formacie epub pojawia sie komunikat błędu

calibre, version 2.10.0
BŁĄD: Nieznany wyjątek: <b>ValueError</b>:too many values to unpack

calibre 2.10 [64bit] isfrozen: True is64bit: True
Windows-7-6.1.7601-SP1 Windows ('64bit', 'WindowsPE')
('Windows', '7', '6.1.7601')
Python 2.7.8
Windows: ('7', '6.1.7601', 'SP1', 'Multiprocessor Free')
Successfully initialized third party plugins: K4PC, K4Mac, Kindle Mobi and Topaz DeDRM && Inept Epub DeDRM && rw2010 && Webook.pl && Manage Series && eReader PDB 2 PML && biblioNETka.pl && Quality Check && Resize Cover && Find Duplicates && fantasta.pl && Ignoble Epub DeDRM && LubimyCzytac && Open With && ksia�ki.wp.pl && Inept PDF DeDRM
Traceback (most recent call last):
File "site-packages\calibre\gui2\save.py", line 104, in tick
File "site-packages\calibre\gui2\save.py", line 167, in do_one_write
File "site-packages\calibre\gui2\save.py", line 292, in writing_finished
File "site-packages\calibre\gui2\save.py", line 318, in updating_metadata_finished
File "site-packages\calibre\gui2\save.py", line 368, in report
File "site-packages\calibre\gui2\save.py", line 331, in format_report
File "site-packages\calibre\gui2\save.py", line 331, in <setcomp>
ValueError: too many values to unpack

nie wiem o co chodzi i czy wszystkie epuby się zapisały