'NID not found' on SATA hdd (FBSD 6.1)

[Foo JH]

Hi all,

I'm using the 6.1 release of FreeBSD. Just installed the OS on a 160GB 
SATA harddisk. While installing a port halfway I get this series of 
error messages:

ad4: TIMEOUT - WRITE_DMA48 retrying (1 retry left) LBA=283609215
ad4: TIMEOUT - WRITE_DMA48 retrying (0 retries left) LBA=283609215
ad4: FAILURE - WRITE_DMA48 status=51<READY,DSC,ERROR> 
error=10<NID_NOT_FOUND> LBA=283609215

Running through the mailing list I notice that something similar happened:
http://lists.freebsd.org/pipermail/freebsd-stable/2004-December/010192.html

However that was on the 5.x series, and the source codes have changed 
since (so I can't do the patch as well).

Does anyone recognise this problem? Is it fixable?

Thanks.