Why is this rss feed invalid?

[ward_bekker@yahoo.com]

The discussed rss feed is : 
http://www.trendsportworld.com/newsfeed/rssfeeduk.asp

I used serveral rss headline readers, and they all can read from this 
feed, but the RSS Validator of http://aggregator.userland.com/ does 
not like my rss yet.

error :  

"Sorry, your RSS source did not validate. Here's the error message, 
it may be cryptic. "Can't create item "." because "" is an illegal 
name." 

What did i do wrong?

With kind regards,

Ward Bekker