Trimmed all past discussion just to save space.

PROGRESS:
- The comma should NOT be there as it is not part of the type, it is an
option allowing a user to do the mount.
- The reason the first two and the last two fail is for some reason the file
is not found even though it is really there.  I suspect something like wierd
syntactical thing or a buffer overflow, or ...   I will have to look at this
more.
- When I dumped the comma and did a sudo mount -a, I got

larry@fogtest:~$ sudo mount -a
> mount: special device
> /home/larry/isofiles/ubuntu/10.04/ubuntu-10.04.02-desktop-i386.iso does not
> exist
> mount: special device
> /home/larry/isofiles/ubuntu/10.04/ubuntu-10.04.01-desktop-amd64.iso does not
> exist
> mount: /home/larry/isofiles/ubuntu/10.10/ubuntu-10.10-desktop-i386.iso is
> not a block device (maybe try `-o loop'?)
> mount: /home/larry/isofiles/ubuntu/10.10/ubuntu-10.10-desktop-amd64.iso is
> not a block device (maybe try `-o loop'?)
> mount: special device
> /home/larry/isofiles/ubuntu/11.04/ubuntu-11.11-desktop-i386.iso does not
> exist
> mount: special device
> /home/larry/isofiles/ubuntu/11.04/ubuntu-11.11-desktop-amd64.iso does not
> exist
>

so I tried the following an got back where I started so I think I can put
the loop back now and work at figuring out why it can find the legitimate
files.

larry@fogtest:~$ sudo mount -a -o loop
> /home/larry/isofiles/ubuntu/10.04/ubuntu-10.04.02-desktop-i386.iso: No such
> file or directory
> /home/larry/isofiles/ubuntu/10.04/ubuntu-10.04.01-desktop-amd64.iso: No
> such file or directory
> /home/larry/isofiles/ubuntu/11.04/ubuntu-11.11-desktop-i386.iso: No such
> file or directory
> /home/larry/isofiles/ubuntu/11.04/ubuntu-11.11-desktop-amd64.iso: No such
> file or directory
> larry@fogtest:~$ mount
> /dev/sda1 on / type ext4 (rw,errors=remount-ro)
> proc on /proc type proc (rw,noexec,nosuid,nodev)
> none on /sys type sysfs (rw,noexec,nosuid,nodev)
> none on /sys/fs/fuse/connections type fusectl (rw)
> none on /sys/kernel/debug type debugfs (rw)
> none on /sys/kernel/security type securityfs (rw)
> none on /dev type devtmpfs (rw,mode=0755)
> none on /dev/pts type devpts (rw,noexec,nosuid,gid=5,mode=0620)
> none on /dev/shm type tmpfs (rw,nosuid,nodev)
> none on /var/run type tmpfs (rw,nosuid,mode=0755)
> none on /var/lock type tmpfs (rw,noexec,nosuid,nodev)
> none on /lib/init/rw type tmpfs (rw,nosuid,mode=0755)
> rpc_pipefs on /var/lib/nfs/rpc_pipefs type rpc_pipefs (rw)
> nfsd on /proc/fs/nfsd type nfsd (rw)
> binfmt_misc on /proc/sys/fs/binfmt_misc type binfmt_misc
> (rw,noexec,nosuid,nodev)
> gvfs-fuse-daemon on /home/larry/.gvfs type fuse.gvfs-fuse-daemon
> (rw,nosuid,nodev,user=larry)
> /dev/loop0 on /tftpboot/howtogeek/linux/ubu1010DL32 type iso9660
> (rw,noexec,nosuid,nodev)
> /dev/loop1 on /tftpboot/howtogeek/linux/ubu1010DL64 type iso9660
> (rw,noexec,nosuid,nodev)
>


-- 
Dazed_75 a.k.a. Larry

The spirit of resistance to government is so valuable on certain occasions,
that I wish it always to be kept alive.
  - Thomas Jefferson