[flexcoders] LCDS : ReferenceError: Error #1056:

[Besite - Bart]

Hi People,

I am using the Data Management Service of Livecycle to keep track of 
users logged in.
When I call the fill method the first time, everything works fine.  I 
get back an arraycollection which is shown in a datagrid.

But when I try to add a new user (by clicking on the button "login"), I 
always get the following error :

ReferenceError: Error #1056: Cannot create property size on 
mx.data.UpdateCollectionRange.

I don't find this error in Google and I am seeking on this problem for 2 
days now...  so, the flexcoders list is my last hope :)

Thanks a lot in advance !
Bart

You'll find the client side code below :

<?xml version="1.0" ?>
<mx:Application xmlns:mx="http://www.adobe.com/2006/mxml"; 
creationComplete="initApp();">

    <mx:Script>
        <![CDATA[
        
            /**
              * Deze component bevat alle client-side chat-logica.
              */
            import mybeans.*;

            import mx.messaging.channels.RTMPChannel;
            import mx.messaging.ChannelSet;
            import mx.data.DataService;
            import mx.collections.ArrayCollection;

            public var ds:DataService;

            [Bindable]
            public var users:ArrayCollection;
            public var user:User;

            public function initApp():void
            {
                users = new ArrayCollection();
                ds = new DataService("user");
            
                var myrtmp:RTMPChannel = new RTMPChannel("my-rtmp", 
"rtmp://myremoteserver:2038");
                
                ds.channelSet = new ChannelSet();
                ds.channelSet.addChannel(myrtmp);

                ds.fill(users);
            }

            private function addUser():void
            {          
                var ur:User = new User();
                ur.id = 7;
                ur.name = "test";
                
                  ds.createItem(ur);
            }

        ]]>
    </mx:Script>

        <mx:DataGrid id="dg" dataProvider="{users}" editable="true">
            <mx:columns>
                <mx:DataGridColumn dataField="name" headerText="Name" 
editable="false"/>
                <mx:DataGridColumn dataField="id" headerText="Id"/>
            </mx:columns>
        </mx:DataGrid>
        <mx:Button id="login" label="login" click="addUser()" />
</mx:Application>