It appears that listing a specific jar file, as opposed to *.jar in a
directory, doesn't work right in catalina.properties in 5.0.28. At
least, I just converted a non-working to a working configuration by
replacing a set of jar file pathnames with a pathname to x/*.jar where x
is a dir containing the same two jars.

This seems so unlikely that I don't want to go to bugzilla before giving
someone a chance to give me some idea what I must have missed.