Ohh, ohh, i've solved my problem.
Resize with OS-Selector is very easy.
Now, you can't boot the system.
Download the 1st CD of Redhat Valhalla 7.3.
Boot in the Rescue-Menue.
Mount your system in 'chroot /mnt/sysimage'
Now type 'lilo'.
That's all.
by jo