This official news post is copied verbatim from the RuneScape website. It is copyrighted by Jagex.
It was added on 15 April 2003.
It was added on 15 April 2003.
We are aware that a very small number of players were having problems playing RuneScape after the last update.
I have now updated the client, and made some changes which should fix this problem, so if you were having trouble please try again.
The problem only occurs if you have an extremely old version of Java so most people weren't affected anyway.
However if RuneScape STILL wont work for you then visit www.windowsupdate.com and get all of the 'critical' updates listed there. This should fix the problem. This also has the added benefit that it will fix any security problems your computer has. So if you don't want to be hacked you should visit windowsupdate.com on a regular basis anyway!