Terastation Live Failed Rebuid

[elanmike]

I have a Terastation Live (HS-DHTGL/R5 in which I have been running 4x1.5TB drives in Raid 5 configuration. I use this to back up data from a MAC and external drive. Last week I got an error stating that there were IO errors on one of the drives and needed to be rebuilt. I started the rebuild and could see in the progress in the web interface. The last check I made showed 56%. When I went back a few hours later, I could not access the drive through the web interface. I left for 4 days as I have read the rebuild can take a while, but no luck. Yhr disks stopped being accessed, but the display on the NAS still said rebuilding - and code I18. When the drive hung, it also showed another error - E11. 

I unplugged and powered back up the NAS. Now I 've set it off to rebuild again. Can anyone offer any suggestions as to what may be going wrong? The disks are 98% full, so I am concerned there is not enough disk 'scrub' area for a rebuild. Is this possible?

If the Terastation cannot rebuild, can the drives be moved to another NAS in Raid 5 configuration to perform the rebuild? Not sure if all NAS 5 drives work the same.

Although the data is also on another dirve,believe it or not, that drive has also crashed, so I need to get the data off the NAS - it has all the video of the kids on there!

Thanks for any help or suggestions you can give.