You need to set the changeLog file to run with the changeLogFile attribute. The changelog is normally relative to a classpath, and the classpath attribute is for listing which dirs to check for the changelog file in.
You can only pass one changelog file at a time. If you have more than one, you can create a master changelog file and the other changelogs in the master.
I pass change log files by either the changeLogFile and by the classpathref attributes. Is it necessary to pass files by both of them? Is there a way to pass several change log files via changeLogFile?