http://support.microsoft.com/kb/319200
http://www.iana.org/assignments/character-sets
change the header to send all the json responses in UTF-8 and not utf-8… VERIFIED 2011/03/08.
2011/03/09 - problem persists!
Look at why the ajax request in the login.html works while all other requests fail in the admin console…
For IE, test using content-type: text/plain vs text/html (without charset param)
For IE and IE ONLY, remove the charset parameter and keep content-type = text/html.
For other browsers, send the charset param.