problem running application

hi, i am facing some problems working from home here. i'm using textpad to compile and save my work. the strange thing is, there's no problem compiling the file, but when i run the java application, it returns

Exception in thread "main" java.lang.NoClassDefFoundError : method3

as far as i know, i saved my file as method3.java which is the same name as my public class, however the thing just doesn't work for me. i've tried with my other files as well and it always returns the same error with the different class names. i have JDK1.5 update 6 installed in my home computer already, and if the same files can run perfectly fine in school, what have i missed out? thank you for any help provided.

[720 byte] By [bluecarrota] at [2007-10-2 10:39:52]