Sometimes people forget that in CLASSPATH you must include the name of the jar file. The JVM won't automatically include all jars in a directory.
Several years ago I gave up fooling with CLASSPATH as an environment variable and went entirely to
ANT controlled compilation.
Here is how I specify the classpath in ANT for a current project - really all on one line in the ANT build.xml:
The joy of ANT is that once set up, compiling that project always has the right classpath and the environment variable is ignored. Yes, there is a learning curve, but you will be glad you did.
Bill