<title type="text"><?php wp_title_rss(); ?></title>
<subtitle type="text"><?php bloginfo_rss("description") ?></subtitle>
- <updated><?php echo mysql2date('Y-m-d\TH:i:s\Z', get_lastpostmodified('GMT'), false); ?></updated>
+ <updated><?php
+ $date = get_lastpostmodified( 'GMT' );
+ echo $date ? mysql2date( 'Y-m-d\TH:i:s\Z', $date ) : date( 'Y-m-d\TH:i:s\Z' );
+ ?></updated>
<link rel="alternate" type="<?php bloginfo_rss('html_type'); ?>" href="<?php bloginfo_rss('url') ?>" />
<id><?php bloginfo('atom_url'); ?></id>