Error when opening ebook

Hi,

Calibre won't launch any ebook. The log is as follow:

calibre, version 0.9.3
ERREUR : Exception non gérée: <b>WindowsError</b>:[Error 5] Acc�s refus: u'C:\\Users\\wam\\Documents\\Calibre\\Chinese Policy Toward Indonesia_ 1949-19\\Mozingo - 2007 (808)\\Mozingo - 2007 - Chinese Policy Toward Indonesia_ 1949-19.pdf'

Traceback (most recent call last):
File "site-packages\calibre\gui2\actions\view.py", line 204, in view_specific_book
File "site-packages\calibre\gui2\actions\view.py", line 278, in _view_books
File "site-packages\calibre\gui2\actions\view.py", line 236, in _view_calibre_books
File "site-packages\calibre\gui2\actions\view.py", line 101, in view_format_by_id
File "site-packages\calibre\gui2\actions\view.py", line 132, in _view_file
File "site-packages\calibre\gui2\actions\view.py", line 122, in _launch_viewer
File "site-packages\calibre\gui2\__init__.py", line 938, in open_local_file
WindowsError: [Error 5] Accès refus: u'C:\\Users\\wam\\Documents\\Calibre\\Chinese Policy Toward Indonesia_ 1949-19\\Mozingo - 2007 (808)\\Mozingo - 2007 - Chinese Policy Toward Indonesia_ 1949-19.pdf'

Any idea?

Thanks