Problem: degraded mode with WD40000A4nc-00

Good afternoon.
There was a problem with our network drive : WD40000A4nc-00
The essence of the problem:
Blinking indicator of identification in red.
In the system log has an entry:

09/15 11:57:31 WDShareSpace daemon.alert wixEvent [895]: Volume Status - Volume ‘DataVolume’ is in degraded mode.

How do I fix this error? Should I replace the hard disk with the following material:

http://wdc.custhelp.com/cgi-bin/wdc.cfg/php/enduser/std_adp.php?p_faqid=2746&p_created=1228262208&p_sid=tDnH_2ak&p_accessibility=0&p_redirect=&p_srch=1&p_lva=1048&p_sp=cF9zcmNoPTEmcF9zb3J0X2J5PSZwX2dyaWRzb3J0PSZwX3Jvd19jbnQ9MTUyLDE1MiZwX3Byb2RzPTAmcF9jYXRzPTAmcF9wdj0mcF9jdj0mcF9zZWFyY2hfdHlwZT1hbnN3ZXJzLnNlYXJjaF9mbmwmcF9wYWdlPTEmcF9zZWFyY2hfdGV4dD1kZWdyYWRlZCBtb2Rl&p_li=&p_topview=1

Or is this problem solved any other way?
Thankyou

If you have a degraded RAID chances are a drive has failed and should be replaced. Make sure when you create the RMA to use the internal drives serial number and not the one on the enclosure, or they will send you a replacement unit instead of just a drive.