unable to build cocoon 2.1.3 sources file

[itpcl]

I have set the JAVA_HOME, ANT_HOME and CATALINA_HOME environment variables.
After download and unzip the cocoon 2.1.3 source file, I type "build war".
As the building process go after loading samples and generating javadocs,
it fails to compile Cocoon.java,
complaining about the org.apache.tools.ant.xxxx.

Then I set CLASSPATH to the ant.jar file. Still cannot compile.

Win2k + Tomcat 4.1.29 + JDK 1.4

Thanks