[SOLVED] Debian - FATAL: Kernel too old, Please upgrade your kernel before installing

I have had a Linode for some time now. I haven't updated it in a while. I am running Debian testing on it.

Recently I wanted to install ntop. During the process it also wanted to update libc, but this caused a problem:

WARNING: this version of the GNU libc requires kernel version 2.6.26 or later. Please upgrade your kernel before installing glibc.

The installation of a 2.6 kernel _could_ ask you to install a new libc
first, this is NOT a bug, and should *NOT* be reported. In that case,
please add lenny sources to your /etc/apt/sources.list and run:
  apt-get install -t lenny linux-image-2.6
Then reboot into this new kernel, and proceed with your upgrade
dpkg: error processing /var/cache/apt/archives/libc6_2.13-10_amd64.deb (--unpack):
 subprocess new pre-installation script returned error exit status 1
configured to not write apport reports

Among other things I tried updating my sources.list to lenny but trying to install that kernel gave me an error about setting initrd.

I've also tried manually installing which eventually lead to errors like FATAL: Kernel too old.

I tried rebooting right in the beginning but am now too wary to try again.

I would prefer to get this system fixed, reinstalling is a last resort.

$ uname -a

Linux miho 2.6.18.8-x86_64-linode1 #1 SMP Thu Apr 10 11:20:13 EDT 2008 x86_64 GNU/Linux

$ cat /etc/apt/sources.list

# the main Debian packages.
deb http://mirror.cc.columbia.edu/pub/linux/debian/debian/ testing main contrib
# Uncomment the deb-src line if you want 'apt-get source'
# to work with most packages.
# deb-src http://mirror.cc.columbia.edu/pub/linux/debian/debian/ testing main contrib
# uncommenting the following line will enable security updates
deb http://security.debian.org/ testing/updates main contrib