At the end of the installation, the computer freezes up.

On a different forum, I found this as the solution:
mkdir /Volumes/Test
mount /dev/<partition id> /Volumes/Test
bless -mount /Volumes/Test -setBoot
umount /Volumes/Test
rm -rf /Volumes/Test

When I type in mount /dev/disk0s1 /Volumes/Test
I get a message saying the resource is busy. Any suggestions?