The error message:
[root@xcat02 etc]# packimage -p compute.ppc64 -a ppc64 -o rhels5.3
Error: Unable to find file exclusion list under /install/custom/netboot/rh or /opt/xcat/share/xcat/netboot/rh/ for compute.ppc64/ppc64/rhels5.3
I think the exclusion list is not neccessary for packimage. One proper method is to check whether the exclusion file exits, if the file is there, "packimage" will use it; if the file is not there, just ignore it.
I have made the code change, and checked in.