Message in /var/log/messages during boot?

[Mike C]

Does anyone know what the following lines in /var/log/messages might mean
or indicate?

Jul  5 11:19:40 physics30 kernel: cdrom: This disc doesn't have any tracks
 I recognize!
Jul  5 11:19:40 physics30 kernel: Buffer I/O error on device sr0, 
logical block 0
Jul  5 11:19:40 physics30 kernel: Buffer I/O error on device sr0, 
logical block 1
Jul  5 11:19:40 physics30 kernel: Buffer I/O error on device sr0,
logical block 2
Jul  5 11:19:40 physics30 kernel: Buffer I/O error on device sr0,
logical block 3
Jul  5 11:19:40 physics30 kernel: Buffer I/O error on device sr0,
logical block 4
Jul  5 11:19:40 physics30 kernel: Buffer I/O error on device sr0,
logical block 5
Jul  5 11:19:40 physics30 kernel: Buffer I/O error on device sr0,
logical block 6
Jul  5 11:19:40 physics30 kernel: Buffer I/O error on device sr0,
logical block 7
Jul  5 11:19:40 physics30 kernel: Buffer I/O error on device sr0,
logical block 8

The machine continues to boot and works OK - but I am puzzled.
This is latest updates F7 with KDE desktop. 

Oddly there is a CDROM icon on the desktop - which is not the case
for other machines running the same setup. The only difference here
is that this install had to be done from the KDE LiveCD rather than 
the DVD iso.