For FreeBSD, man pages on the chown "the ownership of a file may only be altered by a super-user for obvious security reasons." If you're just changing group ownership, you could try the
chgrp command, where the user executing it "must belong to the specified group and be the owner of the file, or be the super-user." Other *ix may vary, but I've not seen one that permits ordinary users to change file ownership for about 15 years.
Information about American English usage here and here. Floating point issues? Please read this before posting. — emc
