I just found the hard way that the ooRexx 4.1 RPM for SLES (and possibly SLED/OpenSUSE as well) does not have the proper requirements to allow it to be installed through AutoYaST. AutoYaST is the unattended installation engine by SUSE.
Since it resolves dependencies at installation time, it'll try to install ooRexx VERY early in the process (and fail) because it does not specify "/bin/ln" and "/sbin/service" as a requirement. Thus, when it tries to execute its script, these utilities are not present.
It does work fine if installed manually after the system is ready, though.
Adding these requirements shouldn't impact the manual installation, and will allow ooRexx to be bundled in unattended installation DVDs.