The error explanation (quoted from Grub's documentation at the website) is:
Grub error 17 : Cannot mount selected partition
This error is returned if the partition requested exists, but the filesystem type cannot be recognized by GRUB.
From what I can tell it's not anything lethal, and probably altering /boot/grub/menu.lst helps. Maybe the disk order is wrong in the configuration or something.
If you need a fixing tool for bootloader problems, try out the "Super Grub Disk" bootdisc (website here
); it allows you to reinstall Grub, among other things, which then allows you to boot the operating system(s) on the machine - including Windows. Or if you want, just alter the existing Grub configuration file to make it work.