how to create flex login system using PHP as the backend

Hi,
I am using flash builder 4 and would like to create a login system using flash builder 4 as the front end and php as the back end.  i found a tutorial that i found on the website but getting this error when i try to run it:
 "'HTTPService' declaration must be contained within the <Declarations> tag since it does not implement 'mx.core.IUIComponent'.      Login.mxml      /Login/src      line 27      Flex Problem"

However, i am not sure where i saved the php file is wrong or not as you see i saved the php file under this root ="C:\wamp\www\mylogin.php"
Pls help thanks

<?xml version="1.0" encoding="utf-8"?>
<s:Application xmlns:fx="http://ns.adobe.com/mxml/2009" 
			   xmlns:s="library://ns.adobe.com/flex/spark" 
			   xmlns:mx="library://ns.adobe.com/flex/mx" minWidth="955" minHeight="600">
	<fx:Script>
		<![CDATA[
			import mx.rpc.events.ResultEvent;
			import mx.controls.Alert;
			
		       private function login():void
			   {  
			       loginservice.send();
			   }
			private function onResult(e:ResultEvent):void
			{
				if (e.result.status == true)
				{
					Alert.show("Signed in successfully", "Success");
				}
				else
				{
					Alert.show("No soup for you", "Failure");
				}
			}
		]]>
	</fx:Script>
	<mx:HTTPService id="loginservice" url="C:\wamp\www\mylogin.php" showBusyCursor="true" method="post" result="onResult(event)">
    <mx:request xmlns="">
	<user>{txtUser.text}</user>
	<pass>{txtPass.text}</pass>
		
		
	</mx:request>
	</mx:HTTPService>
					
	<s:Panel x="37" y="33" width="468" height="294" title="Login">
		<s:Label x="34" y="51" text="Username"/>
		<s:Label x="34" y="85" text="Password"/>
		<s:TextInput x="98" y="46" id="txtUser"/>
		<s:TextInput x="98" y="76" id="txtPass"/>
		<s:Button x="156" y="117" label="Login" id="loginID" click="login()"/>
	</s:Panel>
</s:Application>

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