We have a RHEL3 server with three mysql instances, 3.23.58 (port 3306), 4.1.22 (port 3307), and 5.0.45 (port 3308). The latter two instances are add-ons while the first (3.23.58) is the system default with binaries and libraries installed in /usr/bin and /usr/lib. The WP database is installed in the 4.1.22 instance and DB_HOST in wp-config.php points to "localhost:3307". With this configuration, we get an "unable to connect to database" error. When I add "include('connect.php'); echo mysql_get_server_info();" to index.php, it reports that the database version is 3.23.58. I'm concluding that the apache/php/wordpress is attempting to reach the 4.1.22 instance with 3.23.58 and therefore the error. Can anyone provide any advice on how to tell the specific wordpress/php instance to use a custom configured LD_LIBRARY_PATH and PATH so that it will use the 4.1.22 programs (/usr/local/mysql_4.1.22/bin) and libraries (/usr/local/mysql_4.1.22/lib) without changing the apache server defaults? Or is this not possible?