Mkay, I can see the problem now... Both, yaboot and the fstab seem confused about 2 partitions having the same UUID.

The 'clean' solution would be to delete /dev/sda7 from the partition table. gparted does not show /dev/sda7, but there is a chance that parted will. Enter parted in a terminal (you need to be su), then print at the (parted) command prompt. If some /dev/sda7 is shown here you can delete it from here. Be sure to check the parted manpage.

If this does not work IMHO you can 'repair' the partition table by copying your partitions 1:1 to a external harddisc, write a new Apple partition table on your internal harddisc (with parted or gparted) and copy the partitions back one by one in the desired order.

The other solution is to use /dev/sdaX in /etc/yaboot.conf AND /etc/fstab instead of the UUIDs. In your case just replace UUID=blabla with /dev/sdaX, e.g. root=/dev/sda3. Be sure to do the same thing in fstab too!