Comment #1 on issue 1247 by [email protected]: TransformAntTask depends on Xerces built into Ant which is not present in Ant 1.8.1
http://code.google.com/p/google-caja/issues/detail?id=1247
Current work-around documented http://code.google.com/p/google-caja/wiki/RunningCaja#Problems_running_Ant
