Processing triggers for initramfs-tools ...
    update-initramfs: Generating /boot/initrd.img-2.6.26-2-xen-686
    Errors were encountered while processing:
    linux-image-2.6.26-2-xen-686
    linux-image-2.6-xen-686
    E: Sub-process /usr/bin/dpkg returned an error code (1)

    apt-get dist-upgrade
    Reading package lists... Done
    Building dependency tree... Done
    Calculating upgrade... Done
    0 upgraded, 0 newly installed, 0 to remove and 0 not upgraded.
    2 not fully installed or removed.
    After this operation, 0B of additional disk space will be used.
    Do you want to continue [Y/n]? y
    Setting up linux-image-2.6.26-2-xen-686 (2.6.26-19lenny2) ...
    update-initramfs: Generating /boot/initrd.img-2.6.26-2-xen-686
    Searching for GRUB installation directory ... found: /boot/grub
    warning: grub-probe can't find drive for /dev/sda1.
    grub-probe: error: Cannot find a GRUB drive for /dev/sda1. Check your device.map.

    dpkg: error processing linux-image-2.6.26-2-xen-686 (--configure):
    subprocess post-installation script returned error exit status 1
    dpkg: dependency problems prevent configuration of linux-image-2.6-xen-686:
    linux-image-2.6-xen-686 depends on linux-image-2.6.26-2-xen-686; however:
    Package linux-image-2.6.26-2-xen-686 is not configured yet.
    dpkg: error processing linux-image-2.6-xen-686 (--configure):
    dependency problems - leaving unconfigured
    Errors were encountered while processing:
    linux-image-2.6.26-2-xen-686
    linux-image-2.6-xen-686
    E: Sub-process /usr/bin/dpkg returned an error code (1)

apt-get remove grub