Incorrect "Not Found" error on my site

[freshw10]

Topic issue??

when i click on a post title in my forum i get this;
Not Found
The requested URL /topic,3.msg4.html was not found on this server.

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

The content is obviously there, any idea whats up with this ??

 

[freshw10]

Disregard any further.