[flexcoders] Need Help With This Error -- No service is configured to handle messages of type

[lifeonisland]

I am trying to use Flex Data Services on jboss and I get this error
when I try to access my mxml page.

Does anyone know what causes this error

[MessagingError message='No service is configured to handle messages
of type 'flex.data.messages.DataMessage'.']
        at mx.messaging.config::ServerConfig$/getServiceIdForMessage()
        at mx.data::Metadata$iinit()
        at mx.data::ConcreteDataService$iinit()
        at mx.data::ConcreteDataService$/getService()
        at mx.data.mxml::DataService/set destination()
        at AssemblerTest/::_DataService1_i()
        at AssemblerTest$iinit()
        at _AssemblerTest_mx_managers_SystemManager/create()
        at mx.managers::SystemManager/::initializeTopLevelWindow()
        at mx.managers::SystemManager/::docFrameHandler()


MXML Code

<?xml version="1.0" encoding="utf-8"?>
<mx:Application xmlns:mx="http://www.adobe.com/2006/mxml"; xmlns="*"
layout="horizontal" creationComplete="ds.fill(customers)">


<mx:DataService id="ds" destination="customer" autoCommit="false"
autoSyncEnabled="false"/>
<mx:ArrayCollection id="customers"/>

<mx:Panel title="Customer List" width="100%" height="100%">
<mx:DataGrid id="dg" width="100%" height="100%"
dataProvider="{customers}" enabled="{!ds.commitRequired}">
<mx:columns>
<mx:DataGridColumn dataField="email" headerText="Email" editable="false"/>
<mx:DataGridColumn dataField="firstName" headerText="FirstName"
editable="false"/>
</mx:columns>
</mx:DataGrid>
</mx:Panel>
</mx:Application>


Assembler Code

package com.photo.assemblers.customer;

import flex.data.assemblers.AbstractAssembler;

import java.util.Collection;
import java.util.List;
import java.util.Collections;

import com.elasticpath.domain.customer.Customer;
import com.elasticpath.domain.customer.impl.CustomerImpl;


public class CustomerAssembler extends AbstractAssembler {

    public Collection fill(List list) {

       
System.out.println("CCCCCCCCCCCCCCCCCCALLLLLLLLLLLLLLLLLLLLLLLLED");

        Customer cust = new CustomerImpl();
        cust.setEmail("[EMAIL PROTECTED]");
        cust.setFirstName("Amit");
        return Collections.singletonList(cust);
    }
}