Ok, so I've repaired this...
I've added (bolded text):
unsigned savetobase(){return 0;};
unsigned modifybase(){return 0;};
unsigned searchbase(){return 0;};
unsigned addremove_entry(){return 0;};
unsigned makebackup(){return 0;};
But I think that compiler should interact in other way in this case, not only by showing over and over this message... :/ even if I didn't marked the debug option.
Regards, .angelo.