I have had the problem before. Some things to check are.
Java security make sure that you have the custom client URL approved in the Control Panel -> Java
If that does not work or you are not presented with a Java error message related to security.
then try this. Remove the Salem File completely from the directory (C:\Users\{YOUR USER HERE}\Salem). Remember to back up any custom things like Radar.xml. Then restart by grabbing the Ender or Latiki which ever you prefer and restart by using the JNLP file.
