I have set up MPlayer 0.90rc1-3.2 with similarly recent DVD support on my up-to-date RedHat 8.0 distribution. MPlayer works fine with DVD movies for some time (perhaps even 15 minutes), but then it unexpectedly freezes and so does linux. The /var/log/messages gets filled with these:

kernel: hdc: command error: status=0x51 { DriveReady SeekComplete Error }
kernel: hdc: command error: error=0x54
kernel: end_request: I/O error, dev 16:00 (hdc), sector 2444
kernel: hdc: command error: status=0x51 { DriveReady SeekComplete Error }
kernel: hdc: command error: error=0x54

and so on until I turn the PC off. I completely lose control of my system. This happens every time I play movies: works for some time and then total freeze with log full of errors related to the DVD drive (hdc).

The DVD-ROM drive comes from Liteon (www.liteonit.com) and has ATAPI/E-IDE interface, 16xDVD and 512 KB buffer, multi-read compliant and fast access time.

Can anyone help me with this, please? Is this a hardware, software or configuration problem?

Is DMA enabled on your DVD-ROM? Check
/sbin/hdparm -i /dev/hdc
or
/usr/sbin/hdparm -i /dev/hdc
Sounds like DMA errors.

Thanks for the answer. But yes, DMA is enabled and it does not change the situation.

hdparm -i /dev/hdc results:

Model=JLMS DVD-ROM LTD-166S, FwRev=DS0B, SerialNo=
Config={ Fixed Removeable DTR<=5Mbs DTR>10Mbs nonMagnetic }
RawCHS=0/0/0, TrkSize=0, SectSize=0, ECCbytes=0
BuffType=unknown, BuffSize=0kB, MaxMultSect=0
(maybe): CurCHS=0/0/0, CurSects=0, LBA=yes, LBAsects=0
IORDY=yes, tPIO={min:227,w/IORDY:120}, tDMA={min:120,rec:120}
PIO modes: pio0 pio1 pio2 pio3 pio4
DMA modes: mdma0 mdma1 mdma2
UDMA modes: udma0 *udma1 udma2
AdvancedPM=no
Drive conforms to: device does not report version: 5

hdparm -d /dev/hdc results:

using_dma = 1 (on)

I have the same DVD drive: LTD-166S, which certainly will not use DMA in Linux. The DVD player (xine) reflects this clearly. It goes fine in XP.
However my drive refuses to use DMA (as root):
# hdparm -d 1 /dev/hdc

/dev/hdc:
setting using_dma to 1 (on)
HDIO_SET_DMA failed: Operation not permitted
using_dma = 0 (off)

In my opnion it's a missing or insufficient driver causing this.

NEWS:
By updating the /etc/modules.conf with
options ide-cd dma=1
I succeeded.
# hdparm -d1 /dev/hdc

/dev/hdc:
setting using_dma to 1 (on)
using_dma = 1 (on)

xine plays excellent now.