Errors reading DVDs?

[VirginSnow at vfemail.net]

Hello, DVD aficianados...

I'm trying to play a DVD I just borrowed from the local library (Short
Circuit, 1986 in case you were wondering) but mplayer REALLY isn't
liking the disk.  Debug, debug, debug... and I found out that I can't
even read the DVD with dd. (imagine a hyperbolically puzzled
expression on my face)

What I see looks a bit like this...

  trouble at pleasework$ dd if=/dev/dvd of=/dev/null count=10k conv=noerror,sync
  dd: reading `/dev/cdrom': Input/output error
  1472+0 records in
  1472+0 records out
  dd: reading `/dev/cdrom': Input/output error
  1472+1 records in
  1473+0 records out
  dd: reading `/dev/cdrom': Input/output error
  1472+2 records in
  1474+0 records out
  dd: reading `/dev/cdrom': Input/output error
  1472+3 records in
  1475+0 records out

[and so on and so forth... never seeming to stop]

I'm wondering if anyone else has experienced this.

When I stick in Groundhog Day (also borrowed) or Trading Places (store
bought), it does the same thing.  But, I've watched both Groundhog Day
and Trading on the machine in question... which begs the question: how
can mplayer play a DVD which dd can't even read?  I thought it might
be some form of copy crippl^H^H^H^Hprotection, but none of the discs
in Dune's three-disc set (also library borrowed) exhibit this rather
problematic behavior.  (Who in their right mind would copy-protect
Groundhog Day anyway?)

I noticed that the Short Circuit DVD box is labeled "DUAL LAYER
FORMAT: Layer transition may trigger a slight pause.", but my DVD
drive is also marked "8.5 GB Dual Layer", so I'm thinking this is
probably not a dual layer issue.  Any ideas?

It would be a real shame if this big bowl of popcorn I jus made had to
go to waste... :)