After scheduled Backup still show "not backed up yet"

I has created the incremental scheduled Backup for Hard disk, but after the schedule, the ati 2012 still showing "not backed up yet", but I has mark sure the tib file is created, I has try the re-install the ati and create new backup task, but still not work.

I just re-config my backup task, but now all new create task still has this case, how can I fix this problem?

thanks