I happened to test it in IE 9 but I believe it pops up in other versions as well.
When the user clicks the link to one of our RSS feeds, this message shows up...
ERROR MESSAGE:
Whitespace is not allowed at this location.
Line: 8 Character: 33
<generator>Piano World Piano & Digital Piano Forums - UBB.threads(tm)</generator>
A list of our current rss feeds
http://www.pianoworld.com/forum/ubbthreads.php/topics/2255458/We are on 7.5.8
As always, thanks for any help.