Same problem here after upgrade to 12.04 I think. It's on 1TB Seagate drive that I have running for 4 and a half years now in Mythbuntu setup. It's the OS drive ufortunatelly, I have another WD 2TB which is fine. Started experiencing Mythtv freezes and crashes lately so thought to do a SMARt test and found the errors. AHCI mode enbaled in BIOS for the drive pre install.

00:11.0 SATA controller: Advanced Micro Devices [AMD] nee ATI SB7x0/SB8x0/SB9x0 SATA Controller [AHCI mode] (prog-if 01 [AHCI 1.0])
	Subsystem: Giga-byte Technology Device b002
	Control: I/O+ Mem+ BusMaster+ SpecCycle- MemWINV- VGASnoop- ParErr- Stepping- SERR- FastB2B- DisINTx-
	Status: Cap+ 66MHz+ UDF- FastB2B- ParErr- DEVSEL=medium >TAbort- <TAbort- <MAbort- >SERR- <PERR- INTx-
	Latency: 32
	Interrupt: pin A routed to IRQ 42
	Region 0: I/O ports at ff00 [size=8]
	Region 1: I/O ports at fe00 [size=4]
	Region 2: I/O ports at fd00 [size=8]
	Region 3: I/O ports at fc00 [size=4]
	Region 4: I/O ports at fb00 [size=16]
	Region 5: Memory at fe02f000 (32-bit, non-prefetchable) [size=1K]
	Capabilities: <access denied>
	Kernel driver in use: ahci

[ 9397.726911] ata1.00: exception Emask 0x0 SAct 0x1ff SErr 0x0 action 0x0
[ 9397.726918] ata1.00: irq_stat 0x40000008
[ 9397.726926] ata1.00: failed command: READ FPDMA QUEUED
[ 9397.726941] ata1.00: cmd 60/38:20:6e:29:7a/00:00:1b:00:00/40 tag 4 ncq 28672 in
[ 9397.726950] ata1.00: status: { DRDY ERR }
[ 9397.726955] ata1.00: error: { UNC }
[ 9397.749426] ata1.00: configured for UDMA/133
[ 9397.749455] ata1: EH complete
[ 9532.787964] ata1.00: exception Emask 0x0 SAct 0xfc SErr 0x0 action 0x0
[ 9532.787972] ata1.00: irq_stat 0x40000008
[ 9532.787981] ata1.00: failed command: READ FPDMA QUEUED
[ 9532.787996] ata1.00: cmd 60/e0:10:f6:2b:64/00:00:1b:00:00/40 tag 2 ncq 114688 in
[ 9532.788025] ata1.00: status: { DRDY ERR }
[ 9532.788031] ata1.00: error: { UNC }
[ 9532.867447] ata1.00: configured for UDMA/133
[ 9532.867475] ata1: EH complete
[ 9536.952430] ata1.00: exception Emask 0x0 SAct 0x3e SErr 0x0 action 0x0
[ 9536.952438] ata1.00: irq_stat 0x40000008
[ 9536.952446] ata1.00: failed command: READ FPDMA QUEUED
[ 9536.952460] ata1.00: cmd 60/e0:28:f6:2b:64/00:00:1b:00:00/40 tag 5 ncq 114688 in
[ 9536.952469] ata1.00: status: { DRDY ERR }
[ 9536.952474] ata1.00: error: { UNC }
[ 9536.974938] ata1.00: configured for UDMA/133
[ 9536.974964] ata1: EH complete
[ 9541.683446] ata1.00: exception Emask 0x0 SAct 0x1fff SErr 0x0 action 0x0
[ 9541.683454] ata1.00: irq_stat 0x40000008
[ 9541.683463] ata1.00: failed command: READ FPDMA QUEUED
[ 9541.683477] ata1.00: cmd 60/e0:00:f6:2b:64/00:00:1b:00:00/40 tag 0 ncq 114688 in
[ 9541.683487] ata1.00: status: { DRDY ERR }
[ 9541.683492] ata1.00: error: { UNC }
[ 9541.705986] ata1.00: configured for UDMA/133
[ 9541.706020] ata1: EH complete
[48304.968186] ata1.00: exception Emask 0x0 SAct 0x3ff SErr 0x0 action 0x0
[48304.968195] ata1.00: irq_stat 0x40000001
[48304.968203] ata1.00: failed command: READ FPDMA QUEUED
[48304.968218] ata1.00: cmd 60/20:00:9e:73:a2/00:00:1b:00:00/40 tag 0 ncq 16384 in
[48304.968228] ata1.00: status: { DRDY ERR }
[48304.968232] ata1.00: error: { ABRT }
[48304.968238] ata1.00: failed command: READ FPDMA QUEUED
[48304.968251] ata1.00: cmd 60/68:08:c6:73:a2/00:00:1b:00:00/40 tag 1 ncq 53248 in
[48304.968260] ata1.00: status: { DRDY ERR }
[48304.968264] ata1.00: error: { ABRT }
[48304.968269] ata1.00: failed command: WRITE FPDMA QUEUED
[48304.968282] ata1.00: cmd 61/08:10:d7:21:52/00:00:09:00:00/40 tag 2 ncq 4096 out
[48304.968291] ata1.00: status: { DRDY ERR }
[48304.968296] ata1.00: error: { ABRT }
[48304.968301] ata1.00: failed command: READ FPDMA QUEUED
[48304.968314] ata1.00: cmd 60/68:18:e6:72:a2/00:00:1b:00:00/40 tag 3 ncq 53248 in
[48304.968323] ata1.00: status: { DRDY ERR }
[48304.968328] ata1.00: error: { UNC }
[48304.968333] ata1.00: failed command: READ FPDMA QUEUED
[48304.968345] ata1.00: cmd 60/48:20:56:73:a2/00:00:1b:00:00/40 tag 4 ncq 36864 in
[48304.968354] ata1.00: status: { DRDY ERR }
[48304.968359] ata1.00: error: { ABRT }
[48304.968364] ata1.00: failed command: READ FPDMA QUEUED
[48304.968377] ata1.00: cmd 60/68:28:36:74:a2/00:00:1b:00:00/40 tag 5 ncq 53248 in
[48304.968386] ata1.00: status: { DRDY ERR }
[48304.968390] ata1.00: error: { ABRT }
[48304.968395] ata1.00: failed command: READ FPDMA QUEUED
[48304.968408] ata1.00: cmd 60/70:30:a6:74:a2/00:00:1b:00:00/40 tag 6 ncq 57344 in
[48304.968417] ata1.00: status: { DRDY ERR }
[48304.968421] ata1.00: error: { ABRT }
[48304.968427] ata1.00: failed command: READ FPDMA QUEUED
[48304.968439] ata1.00: cmd 60/80:38:1e:75:a2/00:00:1b:00:00/40 tag 7 ncq 65536 in
[48304.968448] ata1.00: status: { DRDY ERR }
[48304.968452] ata1.00: error: { ABRT }
[48304.968458] ata1.00: failed command: WRITE FPDMA QUEUED
[48304.968470] ata1.00: cmd 61/08:40:1f:21:52/00:00:09:00:00/40 tag 8 ncq 4096 out
[48304.968479] ata1.00: status: { DRDY ERR }
[48304.968484] ata1.00: error: { ABRT }
[48304.968489] ata1.00: failed command: WRITE FPDMA QUEUED
[48304.968502] ata1.00: cmd 61/40:48:3f:46:9f/00:00:09:00:00/40 tag 9 ncq 32768 out
[48304.968511] ata1.00: status: { DRDY ERR }
[48304.968515] ata1.00: error: { ABRT }
[48305.028934] ata1.00: configured for UDMA/133
[48305.028975] ata1: EH complete
[48313.505488] ata1.00: exception Emask 0x0 SAct 0x378 SErr 0x0 action 0x0
[48313.505496] ata1.00: irq_stat 0x40000008
[48313.505505] ata1.00: failed command: READ FPDMA QUEUED
[48313.505520] ata1.00: cmd 60/68:30:e6:72:a2/00:00:1b:00:00/40 tag 6 ncq 53248 in
[48313.505530] ata1.00: status: { DRDY ERR }
[48313.505534] ata1.00: error: { UNC }
[48313.508836] ata1.00: configured for UDMA/133
[48313.508868] ata1: EH complete
[48372.469313] ata1.00: exception Emask 0x0 SAct 0x3fef SErr 0x0 action 0x0
[48372.469322] ata1.00: irq_stat 0x40000008
[48372.469331] ata1.00: failed command: READ FPDMA QUEUED
[48372.469346] ata1.00: cmd 60/68:48:96:ac:a2/00:00:1b:00:00/40 tag 9 ncq 53248 in
[48372.469356] ata1.00: status: { DRDY ERR }
[48372.469361] ata1.00: error: { UNC }
[48372.491750] ata1.00: configured for UDMA/133
[48372.491788] ata1: EH complete
[48376.786824] ata1.00: exception Emask 0x0 SAct 0x11f8 SErr 0x0 action 0x0
[48376.786832] ata1.00: irq_stat 0x40000008
[48376.786840] ata1.00: failed command: READ FPDMA QUEUED
[48376.786855] ata1.00: cmd 60/48:18:06:ad:a2/00:00:1b:00:00/40 tag 3 ncq 36864 in
[48376.786865] ata1.00: status: { DRDY ERR }
[48376.786870] ata1.00: error: { UNC }
[48376.790124] ata1.00: configured for UDMA/133
[48376.790157] ata1: EH complete
[48387.614989] ata1.00: exception Emask 0x0 SAct 0x5e SErr 0x0 action 0x0
[48387.614998] ata1.00: irq_stat 0x40000008
[48387.615006] ata1.00: failed command: READ FPDMA QUEUED
[48387.615021] ata1.00: cmd 60/48:30:06:ad:a2/00:00:1b:00:00/40 tag 6 ncq 36864 in
[48387.615031] ata1.00: status: { DRDY ERR }
[48387.615036] ata1.00: error: { UNC }
[48387.618338] ata1.00: configured for UDMA/133
[48387.618367] ata1: EH complete

Have to check for bad cable first or maybe the power supply needs upgrade.