[Plugin: WP-ServerInfo] Debug shows following info

A bit of a late response I’m afraid. I came across this topic when I was having the same issue and looking for a solution.

I fixed it on my site by editing the plugin:

Change Line 42 from
add_submenu_page('index.php', __('WP-ServerInfo', 'wp-serverinfo'), __('WP-ServerInfo', 'wp-serverinfo'), 1, 'wp-serverinfo/wp-serverinfo.php', 'display_serverinfo');

to

add_submenu_page('index.php', __('WP-ServerInfo', 'wp-serverinfo'), __('WP-ServerInfo', 'wp-serverinfo'), 'add_users', 'wp-serverinfo/wp-serverinfo.php', 'display_serverinfo');

Also I was getting undefined variable errors in the phpinfo output so to fix these:

Add
$data_usage = '';
After line 486: global $wpdb;

Add
$index_usage = '';
After line 502: global $wpdb;