[CentOS] Problem with mdadm softRAID in CentOS4.5!

I have a server running some dababases in CentOS4.5 fully updated, but
this morning I read this error in messages log:

Trover st0:Block limits 1- 16777215 bytes
******************************************************************
172.25.8.236: Servinaves
ATA ABNORMAL DTATUS 0X20DF
ATA ABNORMAL DTATUS 0X20DF
ATA ABNORMAL DTATUS 0X20DF
ata comand 0x35 timeout, stat 0xd0 host - stat 0x21
atat1: status = 0xd0 Busy
SCSI error: 2000 returns code0x8000002
current sda sense key aborted command
additional sense:Scsi parity error
end- request:110 error, devsda,sector 87008471
********************************************************************
I have mdadm  running RAID1 with two disk!

Thanks in advance!

Regards;
Israel