Does it work if you try again? Looks like this is an issue with mod_python, which cannot accept chunked encoding (https://issues.apache.org/jira/browse/MODPYTHON-222)

We’re not sure under what conditions the client decides to send chunked vs not, but in our testing if you retry it should get through.

strange! we're looking into it.

meanwhile try scribbling it down on paper and taking a picture of it :)