AuroraBob

Molly - Have them try Safari, and uninstall Oracle java if they must. Here is how to uninstall 7 and re-enable 6: http://support.apple.com/kb/HT5559?viewlocale=en_US

I had to downgrade to the Apple version of java (6u65) for it to run on OSX 10.9.1 in Safari 7.0.1. My Oracle Java 7 was really broken, so I uninstalled it via the terminal and re-enabled the Apple version. I was then able to log in and get to 90%. I had to keep telling it to enable and trust, but it worked. That may be an option for those who can't get Java 7 to work.