i do not want to know who else has this problem. i want to know how to FIX it.
please tell me, and others with the same problem, how to fix this:

Autodetecting java
Testing default folder
Checking C:\Program Files\Java\jre6 folder
Found java in C:\Program Files\Java\jre6 folder
Checking C:\Program Files\Java\jre1.6.0_01 folder
Found java in C:\Program Files\Java\jre1.6.0_01 folder
Checking C:\Program Files\Java\jdk1.6.0_16 folder
Found java in C:\Program Files\Java\jdk1.6.0_16 folder
Checking C:\Program Files\Java\jdk1.6.0_17 folder
Found java in C:\Program Files\Java\jdk1.6.0_17 folder
Starting java from "C:\Program Files\Java\jdk1.6.0_17\bin\java.exe"
Exception in thread "main" java.lang.NoClassDefFoundError: com/mojang/minecraft/
MinecraftApplet
        at java.lang.ClassLoader.defineClass1(Native Method)
        at java.lang.ClassLoader.defineClass(ClassLoader.java:616)
        at java.security.SecureClassLoader.defineClass(SecureClassLoader.java:12
4)
        at java.net.URLClassLoader.defineClass(URLClassLoader.java:260)
        at java.net.URLClassLoader.access$000(URLClassLoader.java:56)
        at java.net.URLClassLoader$1.run(URLClassLoader.java:195)
        at java.security.AccessController.doPrivileged(Native Method)
        at java.net.URLClassLoader.findClass(URLClassLoader.java:188)
        at java.lang.ClassLoader.loadClass(ClassLoader.java:303)
        at sun.misc.Launcher$AppClassLoader.loadClass(Launcher.java:301)
        at java.lang.ClassLoader.loadClass(ClassLoader.java:248)
        at java.lang.ClassLoader.loadClassInternal(ClassLoader.java:316)
Caused by: java.lang.ClassNotFoundException: com.mojang.minecraft.MinecraftApple
t
        at java.net.URLClassLoader$1.run(URLClassLoader.java:200)
        at java.security.AccessController.doPrivileged(Native Method)
        at java.net.URLClassLoader.findClass(URLClassLoader.java:188)
        at java.lang.ClassLoader.loadClass(ClassLoader.java:303)
        at sun.misc.Launcher$AppClassLoader.loadClass(Launcher.java:301)
        at java.lang.ClassLoader.loadClass(ClassLoader.java:248)
        at java.lang.ClassLoader.loadClassInternal(ClassLoader.java:316)
        ... 12 more
Could not find the main class: Main.  Program will exit.
ERROR: Failed to run minecraft
JAVA6="C:\Program Files\Java\jdk1.6.0_17\bin\java.exe"



FOR EVERYONE WHO IS BLIND TO NOT READ THIS, THE MINECRAFT JAR IS ALREADY PLACED IN THE LIB. AND THIS ERROR OCCURED WHEN MINECRAFT BETA CAME OUT!!!