RE: /web
Apache RPM's on RedHat use /var/www. I'd say use /var/lib/openacs/servername/whatever -- or even /var/openacs/servername/whatever -- although that is not strictly FHS compliant. The first one is.
The best thing is to variablize the dependency on the hardcoded /web out -- what's wrong with a $serverhome, $webroot, or similar? This way any number of configs can be supported -- and, more importantly, multiple ACS installations per box (one per AOLserver 3.0 process) can be supported easily.
RE: JRE vs JDK. Thanks for the clarification, Dan.