posting: SERVER_RESPONSE_CLOSE

Every time I try to post or make a comment, I get this server message.
SERVER_RESPONSE_CLOSE
If I am posting, the post gets posted anyway.
If I am commenting, the comment doesn’t get posted. wp-comments-post.php
This is a server message, but my static content is being served ok, and so is my other python-based cms and pages with php include statements. (I’m linux + gentoo)
I’ve been having a lot of problem with spam comments, so I turned comments off for a while. But I turned them back on, and that seemed to make no difference.
I’m not on the latest version of wordpress (and have been meaning to post soon).
If you want to try it out, you can http://www.imaginaryplanet.net/weblogs/idiotprogrammer/index.php
Any guesses about what this is all about?
Robert