Attempted updating from v2.3.3 to v2.5 (as per the instructions at http://codex.wordpress.org/Upgrading_WordPress) - FAILED. Access returned an error "Fatal error: Call to undefined method wpdb::supports_collation() in /var/www/html/cms_list/wordpress/wp-admin/includes/schema.php on line 9" (can't recall whether this was via the admin/upgrade/public interface).
Reverted the Upgrade and attempted to install a fresh version of v2.5, in parallel with the existing version (to try and work around and identify the cause).
Public Interface returns a blank page.
Attempts to access the wp-admin interface shoots me to a URL "http://172.27.105.200/cms_list/wordpress/wp-admin/upgrade.php?_wp_http_referer=%2Fcms_list%2Fwordpress_2_5%2Fwp-admin%2F"
NOTE: The working v2.3.3 install is at /cms_list/wordpress/ and the v2.5 install is at /cms_list/wordpress_2_5/, meaning that either v2.5 has trouble handling a URI with underscores, or it is somehow getting confused and shooting me back to the older install.
All confused here (and probably confusing others, in turn), so anyone with any questions to help (us all) clarify the issue are welcome.