[PHP-WIN] Problem with pg_trace

[Gene.Brumm]

I'm not sure if this the place to ask for help, but I have tried the
FAQ, Knowledge Base, etc. to no avail. I am using the Windows version
5.0.3 of PHP running on an XP workstation. I can't get the pg_trace
function to work properly. Here is a code snip:
 
$res = pg_trace("C:/PostgreSQLDevHndbk/tmp/trace-log.log", w, $conn);
 
$sql = "SELECT * FROM customer";
$result = pg_exec($conn, $sql);
$rows = pg_numrows($result);
 
for ($i = 0; $i < $rows; $i++)
{
   $myarray = pg_fetch_row($result, $i);
   echo ("Array: $myarray[2] - $myarray[3]<br>\n");
}
 
$res = pg_untrace($conn);
 
The trace-log.log file is generated but is empty. What am I doing wrong?