Thanks for the tip about dumping Stuffit. From the Tomcat webpage (which warns that OSX can't gunzip the files), I guessed that Stuffit was the cause. I was about to test the theory myself when I searched here and found your hint. Dead on. When Stuffit ungzip'd the files, Tomcat failed, when I issued commands the Terminal to ungzip, that version of Tomcat worked.

Unfortunately, I can't say the same for Cocoon. Does anyone know what these screen-filling errors mean? And how to fix it?

root cause

java.lang.NoClassDefFoundError: javax/xml/transform/URIResolver
at java.lang.ClassLoader.defineClass0(Native Method)
at java.lang.ClassLoader.defineClass(ClassLoader.java:486)
at java.security.SecureClassLoader.defineClass(SecureClassLoader.java:111)
at org.apache.catalina.loader.WebappClassLoader.findClassInternal(WebappClassLoader.java:1631)
at org.apache.catalina.loader.WebappClassLoader.findClass(WebappClassLoader.java:926)
at org.apache.catalina.loader.WebappClassLoader.loadClass(WebappClassLoader.java:1360)
at java.lang.ClassLoader.loadClass(ClassLoader.java:290)
at java.lang.ClassLoader.loadClass(ClassLoader.java:253)
at org.apache.avalon.excalibur.component.ExcaliburComponentManager.configure(ExcaliburComponentManager.java:408)
at org.apache.cocoon.Cocoon.configure(Cocoon.java:406)
at org.apache.cocoon.Cocoon.initialize(Cocoon.java:267)
at org.apache.cocoon.servlet.CocoonServlet.createCocoon(CocoonServlet.java:991)
at org.apache.cocoon.servlet.CocoonServlet.init(CocoonServlet.java:308)
at org.apache.catalina.core.StandardWrapper.loadServlet(StandardWrapper.java:916)
at org.apache.catalina.core.StandardWrapper.allocate(StandardWrapper.java:653)
at org.apache.catalina.core.StandardWrapperValve.invoke(StandardWrapperValve.java:214)
at org.apache.catalina.core.StandardPipeline.invokeNext(StandardPipeline.java:566)
at org.apache.catalina.core.StandardPipeline.invoke(StandardPipeline.java:472)
at org.apache.catalina.core.ContainerBase.invoke(ContainerBase.java:943)
at org.apache.catalina.core.StandardContextValve.invoke(StandardContextValve.java:190)
at org.apache.catalina.core.StandardPipeline.invokeNext(StandardPipeline.java:566)
at org.apache.catalina.valves.CertificatesValve.invoke(CertificatesValve.java:246)
at org.apache.catalina.core.StandardPipeline.invokeNext(StandardPipeline.java:564)
at org.apache.catalina.core.StandardPipeline.invoke(StandardPipeline.java:472)
at org.apache.catalina.core.ContainerBase.invoke(ContainerBase.java:943)
at org.apache.catalina.core.StandardContext.invoke(StandardContext.java:2343)
at org.apache.catalina.core.StandardHostValve.invoke(StandardHostValve.java:180)
at org.apache.catalina.core.StandardPipeline.invokeNext(StandardPipeline.java:566)
at org.apache.catalina.valves.ErrorDispatcherValve.invoke(ErrorDispatcherValve.java:170)
at org.apache.catalina.core.StandardPipeline.invokeNext(StandardPipeline.java:564)
at org.apache.catalina.valves.ErrorReportValve.invoke(ErrorReportValve.java:170)
at org.apache.catalina.core.StandardPipeline.invokeNext(StandardPipeline.java:564)
at org.apache.catalina.valves.AccessLogValve.invoke(AccessLogValve.java:468)
at org.apache.catalina.core.StandardPipeline.invokeNext(StandardPipeline.java:564)
at org.apache.catalina.core.StandardPipeline.invoke(StandardPipeline.java:472)
at org.apache.catalina.core.ContainerBase.invoke(ContainerBase.java:943)
at org.apache.catalina.core.StandardEngineValve.invoke(StandardEngineValve.java:174)
at org.apache.catalina.core.StandardPipeline.invokeNext(StandardPipeline.java:566)
at org.apache.catalina.core.StandardPipeline.invoke(StandardPipeline.java:472)
at org.apache.catalina.core.ContainerBase.invoke(ContainerBase.java:943)
at org.apache.catalina.connector.http.HttpProcessor.process(HttpProcessor.java:1012)
at org.apache.catalina.connector.http.HttpProcessor.run(HttpProcessor.java:1107)
at java.lang.Thread.run(Thread.java:496)