[Evolution] Backup/Restore: "Operation not supported!"!

[Maurice Batey <maurice bcs org uk>]

If I select File-->Backup settings I get:

  "The file contents cannot be displayed.
   Operation not supported"

But in Edit-->Plugins it shows  Backup & Restore as 'enabled'.

And if I hit 'OK' it invites me to select the Evol backup file and
shows a default name.

There seems to be some mixup with the validity of the operation.
Are we supposed to just simply ignore the initial warning?

Is there some plugin I should have found somewhere and installed?

-- 
/\/\aurice 
        (Retired in Surrey, UK)     Registered Linux User #487649
          Linux Mandriva 2010.2 32-bit  PowerPack (i686 kernel) 
          KDE 4.5.2  Virtualbox 4.0.2   Firefox 4.0  Evolution 2.30.3