Here is the Grub Manual
this is what it says about that error.
17 : Cannot mount selected partition
This error is returned if the partition requested exists, but the filesystem type cannot be recognized by GRUB.
Did you setup your swap partition first? Usualy swap is hda5 depending on how you set up your partitions. /boot / /home swap or the easy way is to have a root / partition and then a swap.
Take a look a this Grub howto by saikee Here
it's very good.