I have migrated from 2.1.6 to 2.2.0 by copying Data.fs. Everything works except when I try to create a new ZClass, I get "Could not load oid" error. Any help how to fix it is appreciated.

Just checking - but did you also reinstall (from the original tgz's) all of the products you make have based your zclasses on? I have seen oids on standard output until I had fully reinstalled optional products. If in doub, reinstall everything listed under control-panel, products. maybe nothing to do with it of course .. Jonathan