This problem can be caused by:
Running 64bit JavaTry uninstalling Java and downloading the 32 bit version from www.java.com (even if you have a 64 bit machine).
A Firewall blocking your connection to the Hub.Check that your firewall is allowing Java. You can try disabling it completly and see if you can connect - then you know it's the firewall. Re-enable it and figure out which rules to apply. If you find a combination which works, please let me know and I'll post it here for others!