F 18 disk management tool

[Paul Erickson]

On switching to F 18, whenever I try to use the "disk management" tool 
under "system tools" I get this message:

There are no filesystems which you are allowed to mount or unmount.
Contact your administrator.

In previous versions of Fedora, I could access this tool without
difficulty. What do I need to do to make this tool accessible?

Thanks in advance.

cheers, Paul