Did you post the entire "fdisk -l" output? If you did, then linux is not seeing your "secondary slave" drive. In fact, it is only showing the primary master.
Are you sure that your new drive is plugged in as secondary slave? Do you have two hard drives in your system?
You do have a vfat partition on /dev/hda5. If you are confused about your drive lettering, then I would edit your /etc/fstab and change hdd5 to hda5.
If you're sure that you have two hard drives, and one is secondary slave, then linux isn't seeing it for some reason. Start in your boot up log (probably /var/log/boot.msg).