Tomcat 7.0.25 on an AS/400, V5R4, Another try. Help?

Last week, I posted the following on the Tomcat support list, and while I've gotten back a few replies, I haven't yet found the problem.

Theoretically, I've ironed out the bugs concerning which JVMs Tomcat
will run under (i.e., the ones in QOpenSys, rather than the "classic" ones), but it still crashes on takeoff. Maybe somebody here knows something that might help?

The STDOUT from attempting to start Tomcat is as follows:

/wintouch/tomcat/bin/catalina.sh: 001-0019 Error found searching for command tty. No such path or directory.
Using CATALINA_BASE: /wintouch/tomcat Using CATALINA_HOME: /wintouch/tomcat Using CATALINA_TMPDIR: /wintouch/tomcat/temp Using JRE_HOME: /QOpenSys/QIBM/ProdData/JavaVM/jdk60/32bit Using CLASSPATH: /wintouch/tomcat/bin/bootstrap.jar:/wintouch/tomcat/bin/tomcat-juli.jar

Which is to say, /QOpenSys/QIBM/ProdData/JavaVM/jdk60/32bit/jre is a JVM
that, so far as I'm aware, doesn't have any problems with Tomcat.
Everything above is exactly the same as in a successful launch on our
V6R1 box.

And Catalina.out is mercifully short this time:

java.lang.ClassNotFoundException: org.apache.catalina.startup.Catalina
at java.net.URLClassLoader.findClass(URLClassLoader.java:432) at java.lang.ClassLoader.loadClass(ClassLoader.java:642) at java.lang.ClassLoader.loadClass(ClassLoader.java:608) at org.apache.catalina.startup.Bootstrap.init(Bootstrap.java:236) at org.apache.catalina.startup.Bootstrap.main(Bootstrap.java:425)

It's obviously trying to tell me SOMETHING, but I can't determine WHAT
it's trying to tell me.

Any ideas? I don't see the class it's complaining about in either of the
two JARs listed on the classpath dumped to STDOUT, but if that were the
problem, it wouldn't work here, either.

--
JHHL