If you are migrating Silverlight applications that were created for the Silverlight 2 Beta 2 release or earlier to the final release of Silverlight 2, you are going to need to get the newest Silverlight 2 Tools for Visual Studio 2008 and recompile your project(s).
1. Get the newest version of Silverlight 2 Tools for Visual Studio 2008. You can get these tools from the SDK or online at Getting Started. You may have to uninstall any old tools before doing this install.
2. Open your old project (e.g. .csproj file). A dialog will come up notifying you that your project was created with an older version of Silverlight tools and asks you if you want to upgrade your project. Click the Yes button.
3. Open all of the HTML files and change:
· The Silverlight MIME type from application/x-silverlight-2-b1 or application/x-silverlight-2-b2 to application/x-silverlight-2.
When the XAP is served from a different domain than the host HTML page, Silverlight will validate that the MIME type (Content-Type response header) returned on the HTTP response is application/x-silverlight-app. You are required to add an entry for the Silverlight XAP MIME type to your .htaccess file — e.g. AddType application/x-silverlight-app xap.
Note IIS7 shipped with the right MIME type configurations for Silverlight XAPs. No action is required if you are using IIS7.