Updated from 3.0 to 3.3.2 > undefind function get_current_screen()

Hello,

I updated a client’s network from 3.0 to 3.3.2 for (obvious) security reasons. Since I have updated, I haven’t been able to access the network admin page. I have a 500 error generated by a PHP Fatal Error :

[error] [client CLIENT_IP] PHP Fatal error: Call to undefined function get_current_screen() in /path/to/wordpress/wp-admin/network/settings.php on line 22, referer: http://DOMAIN/wp-admin/index.php

I have read this thread -> http://wordpress.org/support/topic/network-dashboard-gives-error-500-though-main-site-and-its-admincp-load-file?replies=38

I followed the instructions given by Ipstenu. Nothing worked. Here’s a list of the things I tried :

– Disabling plugins
– Make a manual re-install
– Make a fresh install
– Repair and optimize DB
– Check permissions
– Check if there are no conflicting usernames/emails

So now is the point where I can’t get further by my self and need help.

If useful, here are bits the server config :

OS: CentOS 5.6
php -v : PHP 5.2.10
mysql -v : MySQL 5.0.77

This should be sufficient for WP 3.3.2 (even if a bit too old for my liking).

Anybody got an idea?

Thanks in advance!