1. Make sure you have the latest version of Java: https://www.java.com/verify
2. Clear Java cache: Java Control Panel -> General -> Settings -> Delete Files
3. Make sure (outgoing) ports 80, 443 and 10443 are not blocked on your firewall and/or router.
If the cache cleaning does not help, it could be an issue with the proxy settings - at least on linux, javaws uses the system default proxy settings, while the application only works for an direct connection. Run javaws without parameters, the control panel should start, select Network Settings, choose Direct Connection
Yes clean java or install new version of java or try it on another computer . I could not get it to work on two laptops . Cleaned Java cache on both and it worked on one ...the other one still won't launch . Don't want to start messing with proxies so just used my notebook .