When I try to start Runescape I get an error message that says: CLassNotFoundException and lists Rs2Applet.class. How do I fix this so I can play?
Your firewall blocks Java from downloading the RuneScape applet. Try configuring the firewall to allow Java. As some firewalls cause problems specifically with Java 7, downgrading to Java 6 may help.
Source: Jagex Support Page
Disable any proxies or proxy add ons you might have.Had the same issue and disabling the data compression proxy addon in chrome did the trick.