We recently ran into the problem described below while trying to run <xmltask> on AIX.
 
http://permalink.gmane.org/gmane.comp.java.ant.xmltask/545
 
Rather than importing the org.apache API mentioned at the link above it seems the better plan of action would be to remove the dependency on internal API and re-write the code to use Public API:
 
http://docs.oracle.com/javase/1.5.0/docs/api/javax/xml/xpath/package-summary.html
 
Is there a specific reason that the internal classes had to be used that would prevent such a re-write?
Thanks,
Troy Harris