[CentOS] error --- > any idea ?? Kernel: Additional sense: Invalid command operation code

Hi All
My system is CentOS release 4.4 (Final) and for the last few days my system
si getting rebooted ... i really cant find out any reason why ... but on
 the messages found in the var/log/ ...here is what i got .

Aug 10 04:31:34 spam2 kernel: FAILED
Aug 10 04:31:34 spam2 kernel: status = 1, message = 00, host = 0, driver =
08
Aug 10 04:31:34 spam2 kernel: Current sd: sense key Illegal Request
Aug 10 04:31:34 spam2 kernel: Additional sense: Invalid command operation
code
Aug 10 04:31:34 spam2 kernel: FAILED
Aug 10 04:31:34 spam2 kernel: status = 1, message = 00, host = 0, driver =
08
Aug 10 04:31:34 spam2 kernel: Current sd: sense key Illegal Request
Aug 10 04:31:34 spam2 kernel: Additional sense: Invalid command operation
code
Aug 10 04:31:34 spam2 kernel: FAILED
Aug 10 04:31:34 spam2 kernel: status = 1, message = 00, host = 0, driver =
08
Aug 10 04:31:34 spam2 kernel: Current sd: sense key Illegal Request
Aug 10 04:31:34 spam2 kernel: Additional sense: Invalid command operation
code
Aug 10 04:31:34 spam2 kernel: FAILED
Aug 10 04:31:34 spam2 kernel: status = 1, message = 00, host = 0, driver =
08
Aug 10 04:31:34 spam2 kernel: Current sd: sense key Illegal Request
Aug 10 04:31:34 spam2 kernel: Additional sense: Invalid command operation
code
Aug 10 04:31:34 spam2 kernel: FAILED
Aug 10 04:31:34 spam2 kernel: status = 1, message = 00, host = 0, driver =
08
Aug 10 04:31:34 spam2 kernel: Current sd: sense key Illegal Request
Aug 10 04:31:34 spam2 kernel: Additional sense: Invalid command operation
code
Aug 10 04:32:29 spam2 kernel: FAILED
Aug 10 04:32:29 spam2 kernel: status = 1, message = 00, host = 0, driver =
08
Aug 10 04:32:29 spam2 kernel: Current sd: sense key Illegal Request
Aug 10 04:32:29 spam2 kernel: Additional sense: Invalid command operation
code
Aug 10 04:32:29 spam2 kernel: FAILED

Can some one please help me debug this issue . or assist me on what i should
do further .
Thanks
Agnello
-- 
Regards
Agnello D'souza
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