检查字符集是否有效，PHP是否可以访问Oracle库和NLS数据

SQLSTATE[HY000]: OCIEnvNlsCreate: Check the character set is valid and that PHP has access to Oracle libraries and NLS data (/usr/local/src/php-5.4.1/ext/pdo_oci/oci_driver.c:610)。这种问题有遇到过的吗。该怎么解决呀