I downloaded OpenOffice 3 and, sure enough, it doesn't work with PowerWorship. The reason is because they moved the java libraries around and consequently the classpath is now invalid in the pworship.bat launch script. For example, the libraries are no longer under OO_HOME/program/classes.
I will need to create a new launch script for OpenOffice 3, and that should take care of the problem. I will post an update when I have it working on Windows XP.