Just thought I'd mention that the Xerces bug that has been plaguing Tomcat users for a while has been fixed. Maybe the Tomcat developer want to hold off on Tomcat-4.1.15 and release Tomcat-4.1.16 with a bug-fixed Xerces?
See the following for details:
http://nagoya.apache.org/bugzilla/show_bug.cgi?id=13282
Jake
