I found another solution (easier)
Let me start out saying that this does work, but it does involve modifying a system file. go to /System/Library/Frameworks/JavaVM.framework/Versions/A/Resources/. Now, here's the tricky part: get the info of version.plist. Check the preferences and change it from "system" to <administrator's name>. Now open version.plist with vim through Terminal. to do this type:
vim /System/Library/Frameworks/JavaVM.framework/Versions/A/Resources/version.plist
You'll have to change it from:
...
<key>CFBundleShortVersionString</key>
<string>2.0.0</string>
<key>CFBundleVersion</key>
<string>2.0.0</string>
...
to:
...
<key>CFBundleShortVersionString</key>
<string>1.3.5</string>
<key>CFBundleVersion</key>
<string>1.3.5</string>
...
This change will enable you to run the Java 1.4.2 Update 2. Once you've run that and restart it, everything should be fine. (Note: you can change the version number anywhere from 1.3.2 to 1.4.1, but I personally put in 1.3.5 and that worked. If you put in any other value, you'll have the same problem. Also, I have not checked to see if changing the values back to what they should have been after that update would work. If it does, this would of course not involve a restart.)
if you don't know how to use vim, here's a quick run through:
the arrow buttons move the cursor (not the mouse-click)
<i> makes it possible to "insert" changes
hit <esc> when you have finished making the changes
type ":w" to save, ":w!" to force save
type ":q" to quit, ":q!" to force quit