SuSE 8.1 and initrd?

Hello,

after installation of 8.1 and a reboot, the kernel stops booting, 
complaining
about:

VFS: Cannot open root device "sda3" or 08:03

It's a ext3 partition and it seems that he cannot find the module for ext3.
Booting the installed system with the help of the boot-CD, I cannot find an
initrd anywhere.
A "mkinitrd" and changing the /etc/aboot.conf to:

0:1/vmlinuz ro root=/dev/sda3 initrd=/boot/initrd

doesn't help. Now aboot stops with:

/boot/initrd: file not found

What do I have to write into the aboot.conf?
Thanks,

Michael