newusers command - permission denied

In Fedora 17, I'm trying to add a batch of users from a text file using the newusers command. I created a file named users.txt, located in root's home directory. The file is owned by the root user and root group.

The command I enter (logged in as root) is:
newusers /root/users.txt

but I keep getting this error:
newusers: /root/users.txt: Permission denied

I've tried setting the permissions on users.txt to rwxrwxrwx, but that hasn't changed the result. Please help!