I am using the Areca Controller Card (ARC-1680) in my system as well. I have recently upgraded the firmware to ver 1.47 and am still seeing the problems. Strange thing is that I have two devices that are identical other than the fact that one is failing with that error and the other does not.

Drives are ST31500341AS 1.5TB drives. Have a total of 16 in the system. Support has asked me to open up remote support but can't seem to get that to work right now, I am waiting on a response from them still.

Controller Name ARC-1680
Firmware Version V1.47 2009-07-16
BOOT ROM Version V1.47 2009-06-25
SAS Firmware Version 4.7.3.0

Main Processor 1.2GHz IOP348 C1
CPU ICache Size 32KBytes
CPU DCache Size 32KBytes/Write Back
CPU SCache Size 512KBytes/Write Back
System Memory 2048MB/533MHz/ECC
Current IP Address 10.1.8.101