G'day,
Don't use the Seagate AS drives, on a RAID card, they are not supported. (I know that hurts when you have 10x).
Apparently the firmware is "Desktop" orientated so it does not mesh well with the RAID instruction set.

We got a lot of cmd_abort (1143) until we updated the NS drives to the AN05 firmware.

http://kb.open-e.com/entry/90/

Rgds Ben