The quota check page at https://www.ru.ac.za/quota/ is currently not working. When visiting this page you'll get an error suggesting that you are connecting from an IPv6 enabled PC and via a proxy server. The error message isn't accurate; the page itself is not being correctly rendered by the web server.
An upgrade of the University's content management system (TerminalFour) was performed last night. Since the upgrade the quota page is no longer being correctly published the the University's web server, which is the cause of this error. We've informed the Web Unit of the problem.
In the mean time, you can find a list of systems that are believed to be over quota at https://systems.ru.ac.za/quota/reporth.txt