В /etc/fstab есть запись для сидюка? У меня она такая:
/dev/scd0 /media/cdrom0 udf,iso9660 user,noauto,exec,utf8 0 0
Ну и что пишет dmesg | tail ?
[ 472.026433] attempt to access beyond end of device
[ 472.026442] sr0: rw=0, want=3827408, limit=4
[ 472.026453] attempt to access beyond end of device
[ 472.026457] sr0: rw=0, want=1252, limit=4
[ 472.026467] attempt to access beyond end of device
[ 472.026470] sr0: rw=0, want=1028, limit=4
[ 472.026473] UDF-fs: No partition found (1)
[ 472.052388] attempt to access beyond end of device
[ 472.052394] sr0: rw=0, want=68, limit=4
[ 472.052398] isofs_fill_super: bread failed, dev=sr0, iso_blknum=16, block=16