I encountered this problem just now: http://stackoverflow.com/questions/17053890/java-web-start-cannot-find-cached-resource-for-url/17053891
Maybe we have to update the way Jmonkey packages the application in the next couple of days.
I researched about the topic and this is all I got.
I just wanted to bring the attention to this.
Below are just some related info about this.
“This application will be blocked in a future Java security update because the JAR file manifest does not contain the Permissions attribute. Please contact the Publisher for more information. More Information”
“Note to the Publisher: Security features to prevent unauthorized redistribution of your Java application will cause this application to be blocked in the future. See current Java documentation about JAR Manifest entries for the changes that need to be made. Note to users: For any questions, please contact the Publisher who provided you with this application.”