Kjel, I managed to compile the kernel with your config file and the vanilla linux 2.6.18.1. With the "debug" initramfs from DetaolB, I get similar error messages.
I enabled only CONFIG_BLK_DEV_INITRD=y and the problem was gone. Could you please try this ? I can send you separately (off list) the "debug" file. -- Christian -- http://detaolb.sourceforge.net/, a linux distribution for Qemu with Git inside !