Errors were encountered while processing: linux-image-2.6.26-1-amd64

I am trying to set a vps up, using debian 5. I am a beginner to debian, although I have has minimal experience with ubuntu. I am trying to perform a sudo apt-get upgrade, so I can install passenger and nginx so I can host rails apps, but I get an error when the server is trying to install linux-image-2.6.26-1-amd64. I don't know what that is, but passenger wont install nginx without it. Here's what bash shows:

Reading package lists... Done

Building dependency tree

Reading state information... Done

The following packages have been kept back:

linux-image-2.6-amd64

0 upgraded, 0 newly installed, 0 to remove and 1 not upgraded.

1 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-2.6.26-1-amd64 (2.6.26-13lenny2) ...

Running depmod.

Running mkinitramfs-kpkg.

Not updating initrd symbolic links since we are being updated/reinstalled

(2.6.26-13 was configured last, according to dpkg)

Not updating image symbolic links since we are being updated/reinstalled

(2.6.26-13 was configured last, according to dpkg)

Running postinst hook script update-grub.

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.

User postinst hook script [update-grub] exited with value 1

dpkg: error processing linux-image-2.6.26-1-amd64 (--configure):

subprocess post-installation script returned error exit status 1

Errors were encountered while processing:

linux-image-2.6.26-1-amd64

E: Sub-process /usr/bin/dpkg returned an error code (1)

I have read http://osdir.com/ml/debian-user-debian/2009-05/msg02074.html and followed instructions there, but everything seems right. I can't for the life of me figure it out. Could anyone please help?

Thanks in advance,

Tom Brunoli