I have sites on two different servers and I was able to post from flickr to one server but not the other. After going through this with tech support at my hosting company they commented out the following mod security rule:
SecFilterSelective HTTP_Content-Type “!(^application/x-www-form-urlencoded$|^multipart/form-data;)
I am now able to post to both sites.
To echo what has been said: I am unable to get get flickr to post to wordpress. I currently have WP 2.0.1 installed in a subdirectory (e.g. http://www.domain.com/wordpress). I can call the xmlrpc.php file from the browser and I do get message saying “XML-RPC server accepts POST requests only.” When I try from flickr I get “The endpoint you entered was not correct.” I ran a test to see if I could post to my test blog on wordpress.com and it seems to work fine. Has anyone come up with a resolution to this issue? Thanks..