If you are using VistaDB with EntitySpaces under the Compact Framework, and receiving a MissingManifestResourceException, then make sure you are referencing the correct VistaDB dll. At the time of this writing, that is VistaDB.CF20 "VistaDB 3.3 Build 57 - CF Non XML".
See this thread for details:
http://community.entityspaces.net/forums/thread/10589.aspx