JSLint Warning about Ajax data

The following is a snippet of my JS:

$("#submit-email").click(function () {
    var first_name = $("input[name='first_name']").val();
    var last_name = $("input[name='last_name']").val();
    var telephone_number = $("input[name='telephone_number']").val();
    var email_address = $("input[name='email_address']").val();
    var message = $("textarea[name='message']").val();
    $.ajax({
        url: route_send_email,
        method: "POST",
        data: {
            first_name: first_name,
            last_name: last_name,
            telephone_number: telephone_number,
            email_address: email_address,
            message: message
        },
        success: function () {
            $("input[name='first_name']").val("");
            $("input[name='last_name']").val("");
            $("input[name='telephone_number']").val("");
            $("input[name='email_address']").val("");
            $("input[name='message']").val("");
        }
    });
});

JSLint is giving the warning:

Unexpected ': first_name'.

Unexpected ': last_name'.

. . ... up to message.

What exactly is the error? The code works fine, but want to make JSLint happy.

from JSLint Warning about Ajax data