error 404 nav links

The requested URL /(navigation link) was not found on this server.

Additionally, a 404 Not Found error was encountered while trying to use an ErrorDocument to handle the request.

Above, is the error i get for most of my site navigation links on my site. How do i fix this...Can someone plz help me with this???

thanx in advance

using 6.1.6

look here:

http://www.boonex.com/unity/forums/?action=goto&topic_id=404-Error-please-help

you can use the forum search for this questions....