apache1.3.27+php4.2.3+oracle8.17

ora.php :
<?php
$conn =ocilogon("system","manager","Test");
if($conn)
echo "success";
else
echo "fail"
?>

Warning: _oci_open_server: ORA-12154: TNS:could not resolve service name in /usr/local/apache/htdocs/ora.php on line 4


if ora.php delete "Test" such as

ocilogon("system","manager","")

it will echo success

why?pls help me

i can't input chinese sometimes. e.g. now!