Thanks for the quick fix

Check and repair book sizes function works flawlessly now.
Check and rename book paths gives me the the construct_path_name error too:
Spoiler:
calibre, version 1.4.0
FEHLER: Nicht abgefangener Fehler: <b>AttributeError</b>:'LibraryDatabase' object has no attribute 'construct_path_name'
calibre 1.4 [64bit] isfrozen: True is64bit: True
Windows-7-6.1.7601-SP1 Windows ('64bit', 'WindowsPE')
('Windows', '7', '6.1.7601')
Python 2.7.5
Windows: ('7', '6.1.7601', 'SP1', 'Multiprocessor Free')
Traceback (most recent call last):
File "calibre_plugins.quality_check.dialogs", line 51, in do_book_action
File "calibre_plugins.quality_check.check_fix", line 185, in evaluate_book
AttributeError: 'LibraryDatabase' object has no attribute 'construct_path_name'