Chown away from 'nobody'

Somehow, on my G5 running OS 10.5.x, I have ended up with some files with the ownership: nobody:someexistingname

The result prohibits other users on the network to save files to those directories, no matter how they log in.

I have tried repeatedly to:

but to no avail (unfortunately, as you know, chown and chmod return no error messages).

How can I change from "nobody"?

Thanks.

Leopard introduced some new permission features. ACLs mostly. Try getting info on the dir in question and adding users/groups to the dir that way.