Strange behavior on post response

Hi,

I am trying to do a post with jquery in json format. The data that
comes back is always truncated, strangely enough to the exact same
length as the request header content-length size. This only happens
with Firefox 3.

Thanks in advance,

Adrian

Here are the headers

Server nginx/0.7.30
Date Wed, 31 Dec 2008 21:30:27 GMT
Content-Type application/json
Connection keep-alive
X-Powered-By PHP/5.2.6
Set-Cookie PHPSESSID=786ad93713894d2fbc31dbad8db8e953; expires=Wed, 31
Dec 2008 23:30:27 GMT; path=/ USER_ID=2984641; expires=Thu, 01-
Jan-2009 09:10:27 GMT; path=/; domain=getback.com
Expires Sat, 26 Jul 1997 05:00:00 GMT
Pragma no-cache
Cache-Control no-cache
Content-Length 492

Request Headers
Host nginx.getback.com
User-Agent Mozilla/5.0 (Macintosh; U; Intel Mac OS X 10.5; en-US; rv:
1.9.0.5) Gecko/2008120121 Firefox/3.0.5
Accept application/json, text/javascript, /
Accept-Language en-us,en;q=0.5
Accept-Encoding gzip,deflate
Accept-Charset ISO-8859-1,utf-8;q=0.7,*;q=0.7
Keep-Alive 300
Connection keep-alive
Content-Type application/x-www-form-urlencoded; charset=UTF-8
X-Requested-With XMLHttpRequest
Referer http://nginx.getback.com/log-in
Content-Length 492
Cookie
__utma
=106121628.2722233702824369700.1230759025.1230759025.1230759025.1;
__utmb=106121628.1.10.1230759025; __utmc=106121628;
__utmz=106121628.1230759025.1.1.utmcsr=(direct)|utmccn=(direct)|
utmcmd=(none)