Interbase and PHP blues

hey guys,

got another question (looking at no-one in particular .. dahamsta )

I'm trying to get a php script connecting to an Interbase (v.5) dbase. Nothing fancy, just a straight forward connect, query, display, disconnect according to the PHP documentation.

Here's the code:

<?php

$host = 'x' ;
$username = 'y' ;
$password = 'z' ;

if(($dbObj = ibase_connect($host, $username, $password)) != null)
{
$query = 'select * from mytable' ;
$result = ibase_query($dbObj, $query) ;

while($row = ibase_fetch_object($result))
print $row->fieldvalue."\n" ;

ibase_close($dbObj) ;
}
else
echo "Connection Failed\n" ;
?>

I keep getting the following message:

Fatal error: Call to undefined function: ibase_connect() in xxxxxxxx/test.php on line 7

ANy ideas?

(what is it about me and PHP/DBase related questions??)