Here is http transcript.
POST /statuses/update.xml?status=test3+http%3A%2F%2Fbit.ly
%2F18ihCg&source=twitabit HTTP/1.1
Authorization: Basic *********
Host:
twitter.com
Accept: */*
Content-Length: 0
Content-Type: application/x-www-form-urlencoded
HTTP/1.1 200 OK
Date: Wed, 02 Jul 2008 14:46:36 GMT
Server: hi
Content-Type: text/html; charset=UTF-8
Content-Length: 122
Set-Cookie:
_twitter_sess=BAh7CDoJdXNlcmkDJgqpOgdpZCIlYWY1MWYyY2E1OGY3ZDY2YzA2OTNkZGJm
%250AZDg2ZmNhZGEiCmZsYXNoSUM6J0FjdGlvbkNvbnRyb2xsZXI6OkZsYXNoOjpG
%250AbGFzaEhhc2h7AAY6CkB1c2VkewA%253D--
f776b988eb8055175eba43b32cd786df195624ac; domain=.
twitter.com; path=/
Via: 1.1
twitter-web024.twitter.com
Cache-Control: max-age=300
Expires: Wed, 02 Jul 2008 14:51:36 GMT
Vary: Accept-Encoding
Connection: close
Status: 500 Internal Server Error
Content-Type: text/html
<html><body><h1>500 Internal Server Error</h1></body></html>Connection
closed by foreign host.