Ah, okay. Thanks rbm!
I've noticed before that the ref data couldn't be copied, although it was never a showstopper when installing just OACS.
I tried to install again, this time with "install.xml" in acs_root_dir, and everything that should got installed. That is, it continued on with installing the rest of the packages despite the error. The problem "only" occurs when you follow the current .LRN installation docs ...
So, we actually have a one-click installation already. Cool!
/Ola