When viewing my calendar in year view, there are not previous and next links in the calendar navigation.

It possible that my calendar is not configured properly, but here's how I modified the calendar theming to insert the links. First, I copied the calendar-main.tpl.php file into my theme directory. Then I added a conditional statement to check if it's the year view and inserted some PHP:
<?php
// $Id: calendar-main.tpl.php,v 1.2.2.3 2008/10/21 14:20:33 karens Exp $
/**
* @file
* Template to display calendar navigation and links.
*
* @see template_preprocess_calendar_main.
*
* $view: The view.
* $calendar_links: Array of formatted links to other calendar displays - year, month, week, day.
* $calendar_popup: The popup calendar date selector.
* $display_type: year, month, day, or week.
* $mini: Whether this is a mini view.
* $min_date_formatted: The minimum date for this calendar in the format YYYY-MM-DD HH:MM:SS.
* $max_date_formatted: The maximum date for this calendar in the format YYYY-MM-DD HH:MM:SS.
*
*/
//dsm('Display: '. $display_type .': '. $min_date_formatted .' to '. $max_date_formatted);
?>
<div class="calendar-calendar">
<?php if (!empty($calendar_popup)) print $calendar_popup;?>
<?php if (empty($block)) print theme('links', $calendar_links);?>
<?php
if ($display_type == 'year') {
// generate the html for the calendar navigation
$nav = theme('date_navigation', $view);
// define html containers to insert links into
$prev = '<div class="date-prev">';
$next = '<div class="date-next">';
// create link for previous/next year
$prevLink = l('<< prev', 'calendar/' . (arg(1)-1));
$nextLink = l('next >>', 'calendar/' . (arg(1)+1));
// find position of end of previous div container
$prevPos = stripos($nav,$prev) + strlen($prev);
// insert previous link
$nav = substr($nav, 0, $prevPos) . $prevLink . substr($nav, $prevPos);
// find position of end of next div container
$nextPos = stripos($nav,$next) + strlen($next);
// insert next link
$nav = substr($nav, 0, $nextPos) . $nextLink . substr($nav, $nextPos);
print $nav;
} else {
print theme('date_navigation', $view);
}
?>
</div>
?>Now, my calendar has previous and next navigation links.





















