Remove all unecessary spaces within the wp-rss.php file and wp-config.php file. There's an extra space at the bottom part of wp-config.php for example.

Use a fresh wp-rss.php from the wordpress site. Or maybe completely re install all files again, rewriting over the old ones.

Check all your feeds. Your archive feed, your tag feed, etc.

All else fails, check your ATOM feed to see if that works and consider using that instead.

hope this helps evie.

XML Parsing Error: XML or text declaration not at start of entity
Location: http://www.wealthflow.com/blog/?feed=rss2&p=87
Line Number 2, Column 1:<rss version="2.0"
^
And I've done as you suggested in the relevant file and I'm still getting the error. Any ideas?