Check the config of the pix firewall and see if the command
http 0 0 inside or
http 192.168.1.1 255.255.255.0 inside
if any of the above command is in your config then the problem is with the machine.to resolve it you would have to download the latest JVM which you can get from java.com. Since the windows version dont come with the pre-bundled java you would have to download it seperately.
Also as you stated that it worked before and it does not work now also you would have check the internet options and click on advanced tab and then click on restore default.