DeploymentCatalog security error

I'm trying to use the DeploymentCatalog to load my service implementations by MEF. I have the implementation in a single xap. when I use the following code to download it , every thing is ok :

var catalog = new DeploymentCatalog("MyXap.xap");

catalog.DownloadAsync();

I put my xap on a remote server , say on http://ip:90/Myxap.xap, when I write the same code but with the uri , it throws a deployment exception:

var catalog = new DeploymentCatalog(new Uri("http://ip:90/MyXap.xap",UriKind.Absolute));catalog.DownloadAsy开发者_如何学编程nc();

Any help .

Thanks in advance ...

If the XAP you are trying to download is hosted at a different domain (or different port, I think) than your Silverlight App is, you will need a cross domain policy file on the site that hosts your XAP to allow your Silverlight App to access it.

If that's not the problem, you'll need to provide more information. Edit your question to include the full text of the deployment exception you get.