Exception in thread main{resolved}

[System_Error]

This is the error message I get after I compile and then try to run a simple hello world program.
Theres nothing wrong with the syntax.
Heres the error message I get:
Exception in thread "main" java.lang.NoClassDefFoundError: hello

The way I can get this to work is type in the command prompt:
Set CLASSPATH=
and then im able to run the program and it works.(only thing wrong with this is it's temporary)


Here is some info if you need it:

These are my Environment Variables:

Classpath
C:\Sun\AppServer\jdk\lib\tools.jar\ext

Path
C:\Sun\AppServer\jdk\bin


java version 1.4.2_04
java 2 runtime environment, standard edition

Please help me. I have looked everywhere for answers and sources say I have'nt done anything wrong but obviously something is.