Sometimes I got this Error Message in Apache error.log

Permission denied: /var/www/xx/.htaccess pcfg_openfile: unable to check htaccess file, ensure it is readable


I am using Parallels Confixx Software for managing the virtual hosts.
When creating a new RootDirectory for a Domain via Confixx, it will be create with wrong ownerships.
Setting ownerships via console will solve that error:

confixx created it with webX:webX

You need to set it to User and Apache-user:
chown webX:www-data my-Root-Dir

This should help.