Hi,
I just checked with my installation, inside /var/www I have the following additional folders for chrome:
.local
.pki
As far as I remember the pdfs are generated with chrome which is run as user www-data. The user home if www-data is /var/www (I am using ubuntu server).
In your logfile you get a "
mkdir: cannot create directory '/var/www/.local': Permission denied". Try to create the folder and give www-data user and group the right to write to it. This might help.
The .pki folder is only needed if you use self signed certificates, if I remember correctly.
@Paolo: I was talking about the Chrome version installed on the server to convert the html pages to PDF files. That can only be done with google chrome (not firefox or even chromium)
regards
Thomas