It's OK now.
the symlink was chowned by root. I've modified to my web-user and now it's OK.
But it's always the incorrect path

It's allready activated.
You can see the phpinfo here : http://tribal-dolphin.td-blogs.be/phpinfo.php

Thanks.

Hello,
I've the same error with your modifications.
My infos :

/var/www/web12/web/ => My website
/var/www/web12/web/blogs/s9y/ => The serendipity files
/var/www/web12/web/blogs/tribal-dolphin/ => The deployement/* files

My httpd.conf for my website :

<VirtualHost xx.xxx.xxx.x:80>
RewriteCond ...