I have edited the zp-config.php file and i send all the files on my server but i have the message "500 Internal Server Error".
Somebody can help me please?

I would recommend upgrading to the latest SVN version here:
http://www.zenphoto.org/trac/changeset/453/branches/community?old_path=%2F&format=zip
Edit the zp-config.php again and upload.

In fact now it works but not the admin part. I have this code :

Warning: session_start() [function.session-start]: open(/mnt/112/free.fr/e/3/maudmaud8/sessions/sess_b5c4f1898ee083d06af5ddc07c2dcef8, O_RDWR) failed: No such file or directory (2) in /mnt/112/free.fr/e/3/maudmaud8/zenphoto/zen/admin.php on line 2

Warning: session_start() [function.session-start]: Cannot send session cookie - headers already sent by (output started at /mnt/112/free.fr/e/3/maudmaud8/zenphoto/zen/admin.php:2) in /mnt/112/free.fr/e/3/maudmaud8/zenphoto/zen/admin.php on line 2

Warning: session_start() [function.session-start]: Cannot send session cache limiter - headers already sent (output started at /mnt/112/free.fr/e/3/maudmaud8/zenphoto/zen/admin.php:2) in /mnt/112/free.fr/e/3/maudmaud8/zenphoto/zen/admin.php on line 2
MySQL Query ( SELECT * FROM `albums` WHERE `parentid` IS NULL ) Failed. Error: Unknown column 'parentid' in 'where clause'
Warning: Unknown(): open(/mnt/112/free.fr/e/3/maudmaud8/sessions/sess_b5c4f1898ee083d06af5ddc07c2dcef8, O_RDWR) failed: No such file or directory (2) in Unknown on line 0

Warning: Unknown(): Failed to write session data (files). Please verify that the current setting of session.save_path is correct (/mnt/112/free.fr/e/3/maudmaud8/sessions) in Unknown on line 0

If somebody can help me?
thanks!

You need to go to the link ../zen/upgrade.php to get your database updated to the current set of tables.

Thank you it's a bit better, but there are still the messages on the top :

Warning: session_start() [function.session-start]: open(/mnt/112/free.fr/e/3/maudmaud8/sessions/sess_95985e97a2082e68e666729d41f014d3, O_RDWR) failed: No such file or directory (2) in /mnt/112/free.fr/e/3/maudmaud8/zenphoto/zen/admin.php on line 2

Warning: session_start() [function.session-start]: Cannot send session cookie - headers already sent by (output started at /mnt/112/free.fr/e/3/maudmaud8/zenphoto/zen/admin.php:2) in /mnt/112/free.fr/e/3/maudmaud8/zenphoto/zen/admin.php on line 2

Warning: session_start() [function.session-start]: Cannot send session cache limiter - headers already sent (output started at /mnt/112/free.fr/e/3/maudmaud8/zenphoto/zen/admin.php:2) in /mnt/112/free.fr/e/3/maudmaud8/zenphoto/zen/admin.php on line 2

Warning: Cannot modify header information - headers already sent by (output started at /mnt/112/free.fr/e/3/maudmaud8/zenphoto/zen/admin.php:2) in /mnt/112/free.fr/e/3/maudmaud8/zenphoto/zen/admin.php on line 12

Warning: Cannot modify header information - headers already sent by (output started at /mnt/112/free.fr/e/3/maudmaud8/zenphoto/zen/admin.php:2) in /mnt/112/free.fr/e/3/maudmaud8/zenphoto/zen/admin-functions.php on line 48

and down :

Warning: Unknown(): open(/mnt/112/free.fr/e/3/maudmaud8/sessions/sess_95985e97a2082e68e666729d41f014d3, O_RDWR) failed: No such file or directory (2) in Unknown on line 0

Warning: Unknown(): Failed to write session data (files). Please verify that the current setting of session.save_path is correct (/mnt/112/free.fr/e/3/maudmaud8/sessions) in Unknown on line 0