New Bie Question: Doing Flex Salesforce integration for the first time

Question

Dear Friends,
I want to connect to Salesforce using Flex API and I have tried two-three approaches but all in vain.
It give me an error 'INVALID_LOGIN: Invalid username, password, security token; or user locked out.'
PLEASE HELP ME TO FIX THIS .
Also, I would like the highlight the fact that my username and password work only for 'test.salesforce.com' and not for ' login.salesforce.com'. Could it be reason for login failure. I have used the token as suggested.
I have also tried setting different serverURL like ''serverUrl=https://test.salesforce.com/services/Soap/u/9.0 and https://login.salesforce.com/services/Soap/u/9.0 .
Below are two of the techniques I have used. 
(1) Using AIR API.
For this I have done as mentioned in 'http://wiki.developerforce.com/index.php/Force.com_Flex_Quick_Start_Tutorial'.
(2) Trying to tun the below code, that I found in one of the quick start tutorial.
<?xml version="1.0" encoding="utf-8"?>
<s:WindowedApplication 
xmlns:fx="http://ns.adobe.com/mxml/2009" xmlns:s="
library://ns.adobe.com/flex/spark" xmlns:mx="
library://ns.adobe.com/flex/mx" xmlns:salesforce="http://www.salesforce.com/">
<fx:Declarations>
<salesforce:AIRConnection id="force"/>
<!-- Place non-visual elements (e.g., services, value objects) here -->
</fx:Declarations>
<mx:DataGrid id="dgSolutions" right="10" top="10" left="10" bottom="10" />
<fx:Script>
<![CDATA[
import com.salesforce.AsyncResponder; 
import com.salesforce.objects.LoginRequest; 
import com.salesforce.results.LoginResult; 
import com.salesforce.results.QueryResult; 
import mx.collections.ArrayCollection; 
import mx.controls.Alert; 
import mx.rpc.AsyncRequest; 
private function init():void { 
var lr:LoginRequest = new LoginRequest();lr.username =
'myusername'; // I have given my username herelr.password =
'mypassword'; // I have given my password herelr.callback =
new AsyncResponder(loadGrid);force.login(lr);
private function loadGrid(lr:LoginResult):void {Alert.show(
'Hi');force.query(
"Select Id, FirstName, LastName From Contact", 
new AsyncResponder( function (qr:QueryResult):void {dgSolutions.dataProvider = qr.records;
]]>
</fx:Script>
</s:WindowedApplication>
ANYHELP IN THIS REGARD WOULD BE REALLY APPRECIATED.
THANKS IN ADVANCE.

Answer 1

do we need to go the server route to have all these features even though none of it will go though the internet?
"need"? no, but you might prefer to do so.
Let me explain.
First off, there's nothing in Mac OS X Server, per se, that says it's designed for internet-facing applications. Sure, some of the services are internet-leaning, but don't think that internet/non-internet is the deciding factor of whether to use Server over client.
The fact is that much of what you describe can be done via Mac OS X Client, but it can be done much easier with Mac OS X Server. You might find that the hours you save, and the productivity you gain far outweighs the cost of Mac OS X Server.
Case in point, you have three workstations, right? Is each one used by an individual? or are they shared?
If they're shared, would it be easier for any user to be able to log on at any workstation and get their normal desktop environment, preferences, etc? That's something that's easy to do with Mac OS X Server, but not via Mac OS X Client.
You've already touched on shared iCal and contacts, neither of which are part of Mac OS X client, so you'll have to decide how much they're worth to you.
At the end of the day, you'll have to decide for yourself. Of course, you could take the easy option and defer until Mac OS X 10.7 (Lion) comes later in the summer, in which case the server functions are included as optional installs for no additional cost (i.e. buy client and get the Server for free).