You should not apply kernel upgrades like this on our legacy VPS plans due to how they are virtualised. This is only possible on our newer VM plans, dedicated or co-located services.
When updating the kernel on Debian 6, please note there is an issue with xen/grub, requiring you to replace the grub menu file.
After updating the kernel, please run the following -before- rebooting:
cp /boot/grub/menu.lst.xen /boot/grub/menu.lst
Please note that if you do not do this, the VM will not boot normally.
In this instance, please click the 'Reboot in recovery' option within the Cloud control panel. As soon as it boots make an SSH connection to the VM with the username of "root" and password of "recovery".