preupgrade - upgrade error

[Richard Hally]

After completing the download of the needed packages and other things, I clicked 
on reboot. Grub showed me the upgrade to rawhide option. after selecting it, the 
kernel booted and then the following error came up:
"An error occured reading the install from the ISO images. please check your ISO 
images and try again."

the F3 console shows(after some INFO lines):
"04:36:38 ERROR  : failed to open /mnt/isodirbootupgradestage2.img: No such file 
or directory"

the F5 console shows "Running... /bin/mount -n -t ext3 -o ro /dev/sda3 
/mnt/isodir" and that is all.

what is going on? where should I look?

An upgrade directory was created in /boot and it has the initrd.img, the 
stage2.img and the zmlinuz.
Any where else I should check?

Richard