my code(prototype 1.6.1)

Event.observe(window, 'load', function() {
            new Ajax.Request('/modal/order_same/', {
                parameters: {},
                onComplete: function(){alert('err0');},
                onSuccess:function(){alert('err1');},
                onCreate:function(){alert('err2');},
                onFailure:function(){alert('err3');},
                onException:function(){alert('err4');},
                onLoaded:function(){alert('err5');}
            });     
});

or

Event.observe(window, 'load', function() {
            new Ajax.Updater(somelement,'/modal/order_same/', {
                parameters: {},
                onComplete: function(){alert('err0');},
                onSuccess:function(){alert('err1');},
                onCreate:function(){alert('err2');},
                onFailure:function(){alert('err3');},
                onException:function(){alert('err4');},
                onLoaded:function(){alert('err5');}
            });
});

all i get in ff3.7prea5 is "err2". my client says he has ff3.6.3 and same error

firebug console says he's get the response and the status code is 200

works fine in opera, ie 6-8, ff on some computers

any suggestions?