神秘的jQuery AJAX错误需要更多的参数

错误:

uncaught exception: [Exception... "Not enough arguments" nsresult: "0x80570001 (NS_ERROR_XPC_NOT_ENOUGH_ARGS)" location: "JS frame :: http://ajax.googleapis.com/ajax/libs/jquery/1.4.2/jquery.js :: add :: line 5437" data: no]

lzaUserAPI.doAUserSignup(signupUsername, signupPassword, signupEmail, signupFullname, signupCompanyName, signupWebsite, signupPhone, lzaSigninup.onAUserSignedUp);

Ajax函数:

doAUserSignup : function(username, password, email, fullname, companyname, website, phone, callback){

    // Add to server
    var paras = {cmd : 'doAUserSignup', us: username, ps: password, em: email, flnm: fullname, cpnm: companyname, wbst: website, phne: phone};

    $.ajax({
        url: lzaUserAPI.m_url,
        dataType: "json",
        data: paras,
        success: function(ret){callback(ret)}
    });
},

onAUserSignedUp : function (ret) {

    alert ('yea!!!');
    //Todo: log them in
}

有什么想法吗?提前谢谢!