OCI ignoring NLS_DATE_FORMAT parameter

Regardless of how I set the NLS_DATE_FORMAT parameter, when I do a select statement DATE fields are returned in the Oracle default DD-MON-RR format. I can successfully set NLS_DATE_FORMAT using either an environment variable and restarting apache or by using ALTER SESSION SET NLS_DATE_FORMAT = 'DD-MM-RRRR HH24:MI:SS' (I would prefer to use this method). I can verify that the NLS_DATE_FORMAT is set to my desired format both before and after my select statement by running the query SELECT * FROM NLS_SESSION_PARAMETERS WHERE PARAMETER='NLS_DATE_FORMAT' in my script. This problem occurs with both PEAR DB, and with ADODB oci8 drivers. However if I use the ADODB oracle drivers, which use the older ora functions instead of the oci functions, ALTER SESSION works and I am able to retrieve dates in the format I set. Unfortunately, the software I'm working on uses PEAR DB_DataObject, and the PEAR DB Oracle driver uses the oci calls. Version info: Oracle9i Enterprise Edition Release 9.2.0.4.0 - 64bit Production PHP 4.3.4 Apache 1.3.29 Anyone have any ideas or suggestions on why I'm seeing this problem? Thanks, Doug