Well, I'm confused too - it's too weird.
OMG! I am very embarrassed.
It turns out that one of the other tools I have on my machine had copied an old version of db2jcc.jar into my $JAVA_HOME/jre/lib/ext. Removing that file solved the problem. My apologies, and thanks to Myrna for double-checking my work, and giving me the confidence to look elsewhere for the problem. bryan
