I tried the define code (and triple-checked syntax) and I get an error that wp-blog-header.php has undefined functions (directly below the line where it imports wp-config.php). No matter whether I copy and paste from here or manually type in the line of code, it simply won’t work.
Use the value $item[‘pubdate’]
E.g.,
<?php echo $item[‘pubdate’]; ?>
Just make sure that any feed you use has the <pubDate></pubDate> tag pairs.
This is an ongoing issue with rss_fetch(). I have no answers, as I’m finding the same problem. It seems that the feed is always at fault, but you have to verify outside of WP. The actual feed problem will vary.