No idea why you did not get an answer.
I have never used vsftp, and I do not know how to set the hide_file and deny_file parameters, but if you do not want other users to have access to a directory you could just change the permissions. Become root, and change the permissions on that directory so that only the owner can read, write, or execute within it.
You could open a shell, become root, and open konqueror, right click on the folder you want to change, and select the Permissions tab. Uncheck everything except the boxes under Owner. Close it and you should have a folder that is inaccessable to anyone except the owner.