No real help from me but a suggestion.
Have you tested this by uninstalling the Propel Accelerator? If access to your game returns to normal then you have a choice, install and use for normal surfing, or leave uninstalled so you can continue playing RuneScape.
If uninstalling that makes no effect then I have no other ideas.
Using Windows XP SP2 with Intel IV processor, Java(TM)Re version 6u6
Play only one multiplayer game called "RuneScape" and never had problems until recently.
Connection speed dropped from 24-26 kbps to 9.6-12 kbps about week ago when ISP came out with their "propel accelerator". ISP states slow speed is phone company's fault; phone company states not enough static on line to cause problems. I did install the "propel accelerator" and can tell a difference in "surfing" speed; however, now I cannot get onto the multiplayer game I enjoy. I can pull the game up; but when attempting to log in or load one of the worlds to play in, all I get is a red x in top left corner of screen. (Thinking it might be java, I deleted all Java showing in control panel; then went to Java.sun.com and downloaded/reinstalled latest edition, i.e. "jre-6u6-windows-i586-p-iftw.exe" This did not fix the problem.)
I can load the world(s) by choosing the "Signed applet using Sun Java"; but cannot using the "signed applet using 'default java'" as I use to. And loggin in to get my messages is even worse in that I have to click an extra link just to get the screen so I can log in. All this to play the one game I have enjoyed playing for many years without problems.
Can anyone help me figure out what I have done wrong and fix it?