Link Erors site wide

Hi,

I have a linking error message which is common on all my pages. I have searched for the solution to this all day, I suspect it is the post title that is the cause

http://www.tradeshowpromotions.biz/TradeShowNews/10/homier-trade-show/Trade%20Show%20Promtions
error code: 404 (not found), linked from page(s):
http://www.tradeshowpromotions.biz/TradeShowNews/10/homier-trade-show/

Any help would be very much appreciated