Extending X-RAID Voluem failed

Netgear NV+, RAIDiator 4.1.13
Two days ago I added a 1TB disk to an existing X-RAID volume consisting of two 1TB disks and this went smooth. the RAID volume was extended successfully.
Today I wanted to add another 1TB disk, of the same brand as the disk I added 2 days ago.

This did not work out and now I ended up with a screwed up volume with all data gone??
I hope the X-RAID volume including all data can be restored otherwise my trust in data safety with X-RAID will plummet to the lowest place I can imagine.

The volumes TAB shows disk space 0% of 0 Mb used
RAID Disk: <empty space>
Available disks:
Ch 1 : Hitachi HDS721010CLA332 [931 GB] 0 MB free
Ch 2 : Hitachi HDS721010CLA332 [931 GB] 928 GB free
Ch 3 : WDC WD10EZEX-00BN5A0 [931 GB] 0 MB free
Ch 4 : WDC WD10EZEX-00BN5A0 [931 GB] [Dead] <---this was the brand new disk that was added, is it just broken?


Any help that can bring back my data and RAID volume will be much appreciated. If needed I can provide the downloaded log files.

Log of events when adding disk 4:
Thu Mar 13 17:24:31 CET 2014 System is up.
Thu Mar 13 17:24:00 CET 2014 The paths for the shares listed below could not be found. Typically, this occurs when the ReadyNAS is unable to access the data volume. Documents media Backup
Thu Mar 13 17:21:13 CET 2014 Powering off device
Thu Mar 13 17:21:13 CET 2014 Please close this browser session and use RAIDar to reconnect to the device after it is powered back on. System powering off...
Thu Mar 13 17:09:48 CET 2014 The paths for the shares listed below could not be found. Typically, this occurs when the ReadyNAS is unable to access the data volume. Documents media Backup
Thu Mar 13 17:08:32 CET 2014 Blinking disk 3.
Thu Mar 13 17:08:19 CET 2014 Blinking disk 2.
Thu Mar 13 17:08:05 CET 2014 Blinking disk 1.
Thu Mar 13 17:00:44 CET 2014 System is up.
Thu Mar 13 17:00:38 CET 2014 The paths for the shares listed below could not be found. Typically, this occurs when the ReadyNAS is unable to access the data volume. Documents media Backup
Thu Mar 13 16:59:55 CET 2014 Volume scan found no errors.
Thu Mar 13 16:58:28 CET 2014 Rebooting device...
Thu Mar 13 16:58:27 CET 2014 Please close this browser session and use RAIDar to reconnect to the device. System rebooting...
Thu Mar 13 16:54:28 CET 2014 The paths for the shares listed below could not be found. Typically, this occurs when the ReadyNAS is unable to access the data volume. Documents media Backup
Thu Mar 13 16:48:35 CET 2014 System is up.
Thu Mar 13 16:48:16 CET 2014 The paths for the shares listed below could not be found. Typically, this occurs when the ReadyNAS is unable to access the data volume. Documents media Backup
Thu Mar 13 16:46:12 CET 2014 Rebooting device...
Thu Mar 13 16:46:12 CET 2014 Please close this browser session and use RAIDar to reconnect to the device. System rebooting...
Thu Mar 13 16:44:09 CET 2014 RAID sync finished on volume C. The volume is now fully redundant.
Thu Mar 13 16:42:44 CET 2014 Disk capacity expansion error. pvcreate /dev/hdg5
Thu Mar 13 16:42:31 CET 2014 Disk initialization successfully finished. Your system will now begin online expansion. Please do not reboot until you receive notification that the expansion is complete.
Thu Mar 13 16:42:29 CET 2014 Found free space to expand the volume onto, but expansion cannot occur with an active snapshot. Please disable the snapshot at your convenience, then either reboot the system or reinsert the drive to begin expansion.
Thu Mar 13 14:50:25 CET 2014 Disk initialization started. You will be notified via email when the initialization process has been completed. You can also check the progress in Frontview in the Volumes -> RAID Settings tab. Please do not shutdown the system while the initialization is in progress.
Thu Mar 13 14:50:17 CET 2014 Disk add event occurred on SATA channel 4.