[jQuery] Ajax , Json, and error firing instead of success

[elpatator]

Hi people,
I'm trying to make an ajax request, hoping for a clean json response
to come up. Firefox, as usual, behaves like a charm, but when it comes
to IE 6 and 7, it's the error function that's fired.
                $.ajax({
                  url: action,
                  data: data,
                  type: "GET",
                  dataType: "json",
                  error: function(msg) {
               alert("Error: " + msg);
                           alert("URL: " + action);
                           alert("DATA: " + data);
                  },
                  success: function(reponse) {
                                var result = eval("("+reponse+")");
                                alert(result);
                        console.info(reponse);
           [... ...]

Using Charles Web DEbbuging Proxy, I started tracing what's happening
when IE calls for ajax;
here's what Charles says:
{
  "totalPanier": "0,00€",
  "articles": [
    {
      "id": "8a8b8d632481567f01248156fac90009",
      "prixAffiche": "0,00",
      "quantite": "0",
      "libelle": "Carte BEST CADEAUX à montant variable",
      "montantRemise": "",
      "prixTotal": "00,00€"
    },
    {
      "id": "8a8b8d632481567f0124815706910010",
      "prixAffiche": "80,00",
      "quantite": "0",
      "libelle": "Carte BEST CADEAUX 80 Euros",
      "montantRemise": "",
      "prixTotal": "00,00€"
    },
    {
      "id": "8a8b8d632481567f012481570578000f",
      "prixAffiche": "50,00",
      "quantite": "0",
      "libelle": "Carte BEST CADEAUX 50 Euros",
      "montantRemise": "",
      "prixTotal": "00,00€"
    },
    {
      "id": "8a8b8d632481567f012481570549000e",
      "prixAffiche": "30,00",
      "quantite": "0",
      "libelle": "Carte BEST CADEAUX 30 Euros",
      "montantRemise": "",
      "prixTotal": "00,00€"
    },
    {
      "id": "8a8b8d632481567f012481570364000d",
      "prixAffiche": "15,00",
      "quantite": "0",
      "libelle": "Carte BEST CADEAUX 15 Euros",
      "montantRemise": "",
      "prixTotal": "00,00€"
    }
  ]
}
That's ... JSON, perfectlly formated.
Here's for the headers now:
HTTP/1.1 200 OK
Server  Apache-Coyote/1.1
X-Powered-By    Servlet 2.4; JBoss-4.0.3SP1 (build:
CVSTag=JBoss_4_0_3_SP1 date=200510231054)/Tomcat-5.5
Content-Type    application/json;charset=UTF-8
Content-Length  1221
Date    Tue, 08 Dec 2009 18:41:05 GMT

Woot! What the hell am I missing ? Thanks for the great help you could
(and I hope, will) provide !!!