Hi,
First thing what you need is all this 3 instaled:
1. Silverlight 2 beta 2 from MS.
2.VWG 6.1.1 SDK.
3. VWG Silverlight 6.1.1 SDK beta.
When you have all this 3 you compile a VWG Silverlight app and the packager will create the XAP files of you application.
You can see how it works here.
What is the full error that your geting?
What files are missing?
Thanks,
Eyal Albert.