Time Machine using OSX Mavericks

I seem to be having a similar problem with OSX Mavericks and ReadyNAS DUO (V1). Details are:

OSX 10.9.2
ReadyNAS 4.1.13
Wired network at 1Gbps

Whenever I backup I get the following in the OSX eventlog:

2014/03/24 6:07:30,512 PM com.apple.backupd[20758]: Starting manual backup
2014/03/24 6:07:30,519 PM com.apple.backupd[20758]: Attempting to mount network destination URL: afp://ReadyNAS@ReadyNAS._afpovertcp._tcp.local/ReadyNAS
2014/03/24 6:07:32,520 PM com.apple.backupd[20758]: Mounted network destination at mount point: /Volumes/ReadyNAS using URL: afp://ReadyNAS@ReadyNAS._afpovertcp._tcp.local/ReadyNAS
2014/03/24 6:08:02,691 PM com.apple.backupd[20758]: Failed to create backup of Time Machine Information file /Volumes/ReadyNAS/XXXXXXXXXXXXXXX.sparsebundle/com.apple.TimeMachine.MachineID.bckup, error: (null)
2014/03/24 6:09:04,000 PM kernel[0]: hfs: mounted Time Machine Backups on device disk3s2
2014/03/24 6:09:05,834 PM com.apple.backupd[20758]: Disk image /Volumes/ReadyNAS/XXXXXXXXX iMac.sparsebundle mounted at: /Volumes/Time Machine Backups
2014/03/24 6:09:06,977 PM com.apple.backupd[20758]: Backing up to /dev/disk3s2: /Volumes/Time Machine Backups/Backups.backupdb
2014/03/24 6:09:33,187 PM com.apple.backupd[20758]: Event store UUIDs don't match for volume: Macintosh HD
2014/03/24 6:09:59,037 PM mds[35]: (Error) Backup: MDSBackupTask:0x0 Undispatched backup task:319737885 resolved:0 cid:1567889:-1 finished:-1
2014/03/24 6:09:59,038 PM com.apple.backupd[20758]: Stopping backup to allow backup destination disk to be unmounted or ejected.
2014/03/24 6:09:59,105 PM com.apple.backupd[20758]: Indexer unavailable (1)
2014/03/24 6:10:09,000 PM kernel[0]: hfs: unmount initiated on Time Machine Backups on device disk3s2
2014/03/24 6:10:09,138 PM com.apple.backupd[20758]: Cancellation timed out - exiting

Stopping/Starting/Rebooting the ReadyNAS has not helped. Ditto OSX. Last backup now >1month ago.

From reading the forum other than the latest firmware, I don't see any suggestions, but hopefully someone has an idea?

Thanks very much.
Willem