sudo /bin/sh run.sh gives:
2014-12-15 02:00:46 INFO: nhz.javadocResourceBase = "html/doc"
2014-12-15 02:00:46 INFO: nhz.uiServerCORS = "false"
Exception in thread "Thread-0" java.lang.NoClassDefFoundError: Could not initialize class nhz.peer.Peers
at nhz.user.Users.(Users.java:184)
at nhz.Nhz.shutdown(Nhz.java:180)
at nhz.Nhz$1.run(Nhz.java:135)
at java.lang.Thread.run(Thread.java:745)
Anyone any ideas what I'm up against?
Well, it's failing to find nhz.peer.Peers. That could point to any number of things really, but my thoughts basically line up to redownloading the software. There's no files to save, just remove and start again, then set your hallmarks again if you need to.
Have you checked that your Ubuntu is definitely using Java 7 - we did find some issues with running Java 8 on some setups.
If you've already taken some steps, please detail them so we can rule as much out as possible.