When I wanted to play Spiral Knights one day, I clicked the shortcut icon to play the game. I found out that I needed to download this game again. It said it needed about 5 minutes to download. However, when I went back to my computer, it was downloading data at 70% ,but it was going to take 60 minutes, and then 62, and so on. I never saw the load time decrease, or the 70% switch to a different number. I tried logging in at the official website, and tried to play, and got this:

Java Plug-in 1.6.0_29
Using JRE version 1.6.0_29-b11-402-10M3527 Java HotSpot(TM) 64-Bit Server VM
User home directory = /Users/hpua22
----------------------------------------------------
c: clear console window
f: finalize objects on finalization queue
g: garbage collect
h: display this help message
l: dump classloader list
m: print memory usage
o: trigger logging
q: hide console
r: reload policy configuration
s: dump system and deployment properties
t: dump thread list
v: dump thread stack
x: clear classloader cache
0-5: set trace level to
----------------------------------------------------
load: class com.threerings.getdown.launcher.GetdownApplet not found.
java.lang.ClassNotFoundException: com.threerings.getdown.launcher.GetdownApplet
at sun.plugin2.applet.Applet2ClassLoader.findClass(Applet2ClassLoader.java:252)
at sun.plugin2.applet.Plugin2ClassLoader.loadClass0(Plugin2ClassLoader.java:249)
at sun.plugin2.applet.Plugin2ClassLoader.loadClass(Plugin2ClassLoader.java:179)
at sun.plugin2.applet.Plugin2ClassLoader.loadClass(Plugin2ClassLoader.java:160)
at java.lang.ClassLoader.loadClass(ClassLoader.java:247)
at sun.plugin2.applet.Plugin2ClassLoader.loadCode(Plugin2ClassLoader.java:690)
at sun.plugin2.applet.Plugin2Manager.createApplet(Plugin2Manager.java:3045)
at sun.plugin2.applet.Plugin2Manager$AppletExecutionRunnable.run(Plugin2Manager.java:1497)
at java.lang.Thread.run(Thread.java:680)
Exception: java.lang.ClassNotFoundException: com.threerings.getdown.launcher.GetdownApplet
load: class com.threerings.getdown.launcher.GetdownApplet not found.
java.lang.ClassNotFoundException: com.threerings.getdown.launcher.GetdownApplet
at sun.plugin2.applet.Applet2ClassLoader.findClass(Applet2ClassLoader.java:252)
at sun.plugin2.applet.Plugin2ClassLoader.loadClass0(Plugin2ClassLoader.java:249)
at sun.plugin2.applet.Plugin2ClassLoader.loadClass(Plugin2ClassLoader.java:179)
at sun.plugin2.applet.Plugin2ClassLoader.loadClass(Plugin2ClassLoader.java:160)
at java.lang.ClassLoader.loadClass(ClassLoader.java:247)
at sun.plugin2.applet.Plugin2ClassLoader.loadCode(Plugin2ClassLoader.java:690)
at sun.plugin2.applet.Plugin2Manager.createApplet(Plugin2Manager.java:3045)
at sun.plugin2.applet.Plugin2Manager$AppletExecutionRunnable.run(Plugin2Manager.java:1497)
at java.lang.Thread.run(Thread.java:680)
Exception: java.lang.ClassNotFoundException: com.threerings.getdown.launcher.GetdownApplet
load: class com.threerings.getdown.launcher.GetdownApplet not found.
java.lang.ClassNotFoundException: com.threerings.getdown.launcher.GetdownApplet
at sun.plugin2.applet.Applet2ClassLoader.findClass(Applet2ClassLoader.java:252)
at sun.plugin2.applet.Plugin2ClassLoader.loadClass0(Plugin2ClassLoader.java:249)
at sun.plugin2.applet.Plugin2ClassLoader.loadClass(Plugin2ClassLoader.java:179)
at sun.plugin2.applet.Plugin2ClassLoader.loadClass(Plugin2ClassLoader.java:160)
at java.lang.ClassLoader.loadClass(ClassLoader.java:247)
at sun.plugin2.applet.Plugin2ClassLoader.loadCode(Plugin2ClassLoader.java:690)
at sun.plugin2.applet.Plugin2Manager.createApplet(Plugin2Manager.java:3045)
at sun.plugin2.applet.Plugin2Manager$AppletExecutionRunnable.run(Plugin2Manager.java:1497)
at java.lang.Thread.run(Thread.java:680)
Exception: java.lang.ClassNotFoundException: com.threerings.getdown.launcher.GetdownApplet

Help! I love this game, but I can't seem to play it.

P.S. I use a Macintosh computer.