According to Bing
], there is some connection between ADO.NET and silverlight. I would guess that there's an issue with where the table lives, and perhaps there's a local copy that gets modified by then replaced by the server one ? I would suggest reading up on the article I linked to, to understand how ADO.NET works with silverlight. I'd have guessed if the DB was on a server, that silverlight would use webservices to talk to it.