Authentication Failure with pg_pconnect

I'm trying to get phpBB (php Bulletin Board System) running on my website
but it's install program is having problems authenticating with
postgreSQL. I've tried to find out why it won't work and have pretty much
narrowed things down to this one function in the install script. If the
following function doesn't seem flawed in any way, does anyone know why
php my throw this error even though username and password is correct and
user is logging in from localhost:

----
Warning: pg_connect() [function.pg-connect]: Unable to connect to
PostgreSQL server: FATAL 1: IDENT authentication failed for user
"postgres" . in /var/www/html/phpBB2/db/postgres7.php on line 79
phpBB : Critical Error

Could not connect to the database
----

The line 79 it refers to is the line with the pg_pconnect call in the
following function:

----
var $db_connect_id;
var $query_result;
var $in_transaction = 0;
var $row = array();
var $rowset = array();
var $rownum = array();
var $num_queries = 0;

//
// Constructor
//
function sql_db($sqlserver, $sqluser, $sqlpassword, $database,
$persistency = true)
{
$this->connect_string = "";

if( $sqluser )
{
$this->connect_string .= "user=$sqluser ";
}

if( $sqlpassword )
{
$this->connect_string .= "password=$sqlpassword ";
}

if( $sqlserver )
{
if( ereg(":", $sqlserver) )
{
list($sqlserver, $sqlport) = split(":", $sqlserver);
$this->connect_string .= "host=$sqlserver port=$sqlport ";
}
else
{
if( $sqlserver != "localhost" )
{
$this->connect_string .= "host=$sqlserver ";
}
}
}

if( $database )
{
$this->dbname = $database;
$this->connect_string .= "dbname=$database";
}

$this->persistency = $persistency;

$this->db_connect_id = ( $this->persistency ) ?
pg_pconnect($this->connect_string) : pg_connect($this->connect_string);

return ( $this->db_connect_id ) ? $this->db_connect_id : false;
}
---------

PLEASE give me a hand here, at least point me towards people who might
know more. I need to figure this out.

A. Leigh
dash(at)rogue-penguin(dot)com