New PHP Release has Introduced a Bug to MODx 2.0.x

A recent new release of PHP (5.3.6) has addressed this bug - http://bugs.php.net/47802

However, on some installations of MODx the value of $database_connection_charset in the config file is an empty string - This is causing the connection to MySQL to fail; and MODx defaults to the cached resourse countent - as detailed in this forum thread - http://modxcms.com/forums/index.php/topic,62770.0.html

To fix - edit the config file and enter the db character set (can be found in phpMyAdmin or other DB management tools)

[I tried to sign up to register this as a bug, but registation has failed or is buggy or has not been approved yet - no idea as have received no message]

Your charset being blank was the problem. This is not a bug any longer—you probably just had a blank value left over from an early 2.0.x install that did have a bug WRT this configuration value.