Comment 15 for bug 106910

I had a similar mount problem related to a usb hard drive.

Following line in /etc/fstab was the reason for this error:

/dev/sdb1 /media/cdrom0 udf,iso9660 user,noauto,exec,utf8 0 0

ubuntu declared sdb1 as a cdrom drive, which is obviously wrong.
I suggest everybody with this problem to investigate the fstab file.