Timezone Convertion Problem

[eluser]Unknown[/eluser]

Code:

$tz = 'UM5';
$dst = TRUE;

$date_str = '2010-06-04 09:00:00';
            
echo unix_to_human(gmt_to_local(convert_to_gmt(human_to_unix($date_str), $tz, $dst), $tz, $dst), TRUE, 'eu');

The above code is supposed to give output "2010-06-04 9:00:00" but it is showing "2010-06-04 11:00:00"

It is showing 2 more hours. Can anyone tell me why? Did I made any mistake?