Flickr Stumped

See that test post below? It shows that my blog is set up properly at Flickr. The test post always works, and it shows up in my log files as a successful 200 code.

When I try to blog photos via email, though, or using the Blog This link, it always fails. Those show up in my log files with a 502 (Bad Gateway) error.

Flickr support is still looking at it, but they seem stumped.

So, I wonder if anyone else has ever had this problem. If so, how was it resolved?