missing Java classes

I installed the Sun Java 2 SDK on my Linux & WinXP Pro machines.
Everything I run aborts with the same error message.  For example:

$ java kbx
Exception in thread "main" java.lang.NoClassDefFoundError: edu/stanford/TAP/ClientCallback

$ java ex9
Exception in thread "main" java.lang.NoClassDefFoundError: edu/stanford/TAP/Abbrev
        at ex9.main(ex9.java:11)
============ 
Dick McCullough 
knowledge := man do identify od existent done
knowledge haspart proposition list