WC3 Link Checker error on product link

WC3 Link Checker

[douchrti]

Hi,
Hope all is well.
I was trying out the WC3 Link Checker and I got this error.
It involves me putting a link on a product picture.
I dont understand the error.
Can anybody tell me why its wrong to put a link on my site this way?

http://www.example.com/example.gif

What to do: The link is forbidden! This needs fixing. Usual suspects: a missing index.html or Overview.html, or a missing ACL.
Response status code: 403
Response message: Forbidden
Line: 174

[edited by: tedster at 7:29 pm (utc) on June 22, 2007]
[edit reason] switch to example.com [/edit]

[DrDoc]

Software on the server is probably blocking the image based on referrer. This is very common practice. If you know the link is correct and works, ignore the error.