Pool Deactivating

Client with NW6.5 SP7 box is experiencing some pool issues.

Checking server (not my install), SYS and part of VOL1 are on server's local RAID5 array. Other part of VOL1 is located on external storage RAID5 array.

Last week they had a crash and two of the drives in the external array went amber/offline (I was out of town during this). Dell had them power cycle the external box (MD1000) and amber lights gone. Booted server and all OK. But since then, the pool has deactivated twice. Drive lights all good. Error is below:

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11-09-2012 12:30:50 am: NWPA-3.21-0
NWPA-004: The CDM driver deactivated device [V372-A3-D0:0] DELL PERC 5/E
Adapter f/w:1.00 due to a device failure.


11-09-2012 12:30:50 am: COMN-3.25-1092 [nmID=A0025]
NSS-3.00-5001: Pool MBA1/VOL1 is being deactivated.
An I/O error (20204(zio.c[2260])) at block 349884461(file block
-349884461)(ZID 6) has compromised pool integrity.


11-09-2012 12:30:50 am: COMN-3.25-33 [nmID=A0023]
NSS-2.70-5004: Volume MBA1/VOL1 is being deactivated.
An I/O error (20204(zio.c[2260])) at block 349884461(file block
-349884461)(ZID 6) has compromised volume integrity.


11-09-2012 12:30:50 am: COMN-3.25-34 [nmID=60010]
NSS-2.70-5005: Volume MBA1/VOL1 user data write
(20204(zio.c[2282])) to block 208245334(file block 16)(ZID 110123564)
failed.


11-09-2012 12:30:53 am: SERVER-5.70-1534 [nmID=B0013]
Device "[V372-A3-D0:0] DELL PERC 5/E Adapter f/w:1.00" deactivated by
driver due to device failure.
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Any help with this would be appreciated.