Output error message if recurrence is empty
Output error message if recurrence is empty

svn path=/trunk/kdepim/; revision=245511

lefou/kdepim-noakonadi,lefou/kdepim-noakonadi,lefou/kdepim-noakonadi,lefou/kdepim-noakonadi,lefou/kdepim-noakonadi,lefou/kdepim-noakonadi