Bug#473877: linux-image-2.6.24-1-alpha-generic: fail to boot
Kernels since 2.6.23 (and its release candidates) break with an older
version of aboot.
If you have been upgrading your system from Etch or a version of Lenny
from before about middle of last year you will need to upgrade the aboot
package to the latest, and you may need to manually reinstall the boot
block with the swriteboot command. Be aware that if you get this
operation wrong you screw up your computer and won't be able to boot at
all, unless you have another disc in the system that is bootable.
for a hint on using swriteboot and to jump midway into the thread
discussing the aboot issue.