Hi,

If I understood correctly, when your Silverlight application is deployed in a web server this error does not appear; but when the application is locally installed in a machine you are experiencing this error intermittently. Is that correct?

Based on my understanding, if you application is loading the modules loosely (the modules are in XAP files and the Shell does not have a reference to them) then it needs a server to which it can request the modules. As far as I know, even if the application is installed locally it will still try to load the modules through a web request to its server.

• If you are trying installing the application from the production environment, does the application throw this error? And if you run the application with the computer disconnected from the network?
• Also, if you are trying installing the application from a development environment please check if there is a local deployment of the application in your machine (for example a running instance if the Visual Studio web server "cassini") when running the installed application and if this affects the error or not.
  

Regards,

Damian Cherubini
http://blogs.southworks.net/dcherubini