Fatal error: Call to undefined method DateTime::createfromformat()

错误发生在第35行.这是我的代码从第31行到第45行读取的内容

// check database for necessary updates

$update = MysqL_query("SELECT * FROM rent WHERE colour='#3C0'");
while($row_update = MysqL_fetch_array( $update )) {
    $datetime_lower   = DateTime::createFromFormat('d/m/Y',$min);
    $datetime_upper   = DateTime::createFromFormat('d/m/Y',$max);
    $datetime_compare = DateTime::createFromFormat('d/m/Y g:i a',$row_update['pDate']);
    if ($datetime_lower < $datetime_compare && $datetime_upper > $datetime_compare) {
        // date is between do nothing
    } else {
        // date is not between so update
        $update_result = MysqL_query("UPDATE rent SET colour='#F0F0F0' WHERE id=" . $row_update['id'] . " && colour='#3C0'");
        MysqL_close($update_result);
    }
}

我该如何解决这个问题？