There is currently a bug filed at bugzilla.mozilla.org which covers the
problems with java plugin installation. As expected, the xpicleanup
process keeps running after mozilla exits so that it can finish
replacing/changing/removing files that were previously in use.
Consequently, the xpicleanup.dat file contains information on the tasks
that the xpicleanup process was working on at shutdown. I would
appreciate it if one or more of the people that reported problems with
the java plugin install could email me their xpicleanup.dat files before
deleting them so that I can submit them to the mozilla development team
(it would proably be better if you sent them directly to me so as to not
add extra, unwanted traffic to this list).
Also, could you run a 'ps ax | grep xpi' and let me know if there was an
xpicleanup process running when you got the file.
Thanks and sorry for being off topic.