i believe they use a raid 0 setup in that device.
if you open it, you'll have to determine what disk is bad - recovery of a raid 0 system is possible if the disk is still accessable, here some links to free, and other recovery software :
http://www.pcinspector.de/file_recovery/UK/welcome.htm pc Inspector -FREE -
http://www.piriform.com/recuva/download/standard FREE Recuva
http://www.stellarinfo.com/ Stellar
http://www.runtime.org/ GetDataBack
http://www.ontrack.com/ Ontrack
http://www.recovermyfiles.com/ RecoverMyFiles