Drive/Update Error problem

Need help, please

My WD MyBookLiveDuo has always worked well and I keep it updated. But I was was gone for a few days and got two messages: 

Drive failed

Drive failed in location A

Mon 13 Jul 2015 07:28:24 PM CDT

System restart

The system has restarted.

Mon 13 Jul 2015 07:28:41 PM CDT

Got home, green light blinkiing quickly. Checked for updates. Message said " Firmware Update Version found :

MyBookLive 02.43.10-048

Tried update and got message:  Error 31107 Be sure both drives are installed;

Update did not complete.

Looks like one of your disks failed.  You will have to buy a replacement disk.