Your provider has denied read access to the files mentioned there. The PHP/Webserver process cannot read those files.

Either you need to fix the permissions to be readable for the webserver via FTP, or if you do not have permissions for that, ask your hoster/provider to fix it. Also ask them why ...

help instead of myserendipity blog i get this where does it come from and what should i do thanks

http://a.prinstet.free.fr/serendipity/

Warning: file_exists() [function.file-exists]: Unable to access /var/www/free.fr/2/c/a.prinstet/serendipity/plugins/serendipity_event_s9ymarkup/serendipity_event ...