problem with installboot on 4.0.1 install

[Tomas D <u0giene%yahoo.com@localhost>]

Hi,
I'm trying to install 4.0.1 on macppc 9500/200, I boot from cd all looks good. 
I'm getting an error on installboot, here's log;
 
Log started at: Wed Nov 26 08:58:38 2008
Creating disklabel hdd
executing: disklabel -w -r -f /tmp/disktab sd0 'hdd'
executing: /sbin/newfs -V2 -O 1 -b 16384 -f 2048 /dev/rsd0a
/dev/rsd0a: 4005.8MB (8203896 sectors) block size 16384, fragment size 2048
 using 22 cylinder groups of 182.09MB, 11654 blks, 23040 inodes.
...............................................................................
executing: /bin/mkdir -p /targetroot/
executing: /sbin/mount -tffs -o async /dev/sd0a /targetroot/
executing: /bin/mkdir -p /targetroot/etc
Creating /targetroot/etc/fstab.
executing: /bin/mkdir -p /targetroot/kern
executing: /bin/mkdir -p /targetroot/proc
executing: /bin/cp /usr/mdec/ofwboot /targetroot/boot
executing: /usr/sbin/installboot /dev/rsd0a /usr/mdec/bootxx /boot
installboot: Can't write sector 0 of `/dev/rsd0a': Read-only file system
installboot: Set bootstrap operation failed
executing: /sbin/umount /targetroot/
Log ended at: Wed Nov 26 08:59:49 2008
 
Can somebody please tell me how to fix this? 
 
 
Cheers,
Tomas