One thing I forgot to mention is that you need to obtain the install scripts from CVS HEAD rather than from the oacs-5-0 branch as they are not being maintainted on the branch. Here is how I check out the install scripts for a server called myserver
cd /web
cvs -d :pserver:mailto:anonymous@cvs.openacs.org:/cvsroot checkout -d install-myserver openacs-4/etc/install
After that you edit the install.tcl file and then run install.sh as root.
