E-mail messages with error code

Greetings,

I have got some 20 messages alike:

A user tried to go to https://www.koosfoto.com/2009/10/full-moon/comment-page-1/#comment-22 and received a 404 (page not found) error. It wasn’t their fault, so try fixing it.
They came from https://www.koosfoto.com/2009/10/full-moon

with the subject:
Bad Link To /2009/10/full-moon/comment-page-1/#comment-22
(or alike)

I tried myself, going to the picture page, and writing a comment… and it worked fine.

What is this error and how could it be fixed?

Thanks,

Tamas