Trouble replacing drive in RAID 5 setup

I have an SC1400 server with a 3 disk RAID 5 setup. One of the disks failed about a year ago and I bought a new disk, installed and Rebuilt the image........No Problems. I have had another disk fail, and when I attempted to install the new one, the new disk shows Fail and the 2nd disk in the array (which was working) now also shows to be failing. All jumpers are still set as they were and the new disk (which is disk 0 on the Array is set properly.) When I put the new disk back in the box and installed the three drives back in the system, I still get a message that drive 0 and drive 1 are Failing. I have attempted to reformat both 0 and 1 and they still show to be failing.

Luckily, everything is backed up, so I am just trying to get the thing back up again. Is it unusual to have a second drive go down while replacing one? The new drive is a Cheetah 15k, 73 gb and is larger than the old drive but since the speed is the same, it should work. All 3 drives spin up and when attempting to format the two drives that are failing, they spin up and after about 10 minutes of formatiing they show to have failed.