I've just managed to sort out a similar issue with some help from some guys on the Mandriva forum, so I'll share my new-found knowledge!
To load your driver at start up log in as root and go to your /etc/rc.d. In that folder you'll find rc.local. Edit this file with your favourite text editor (nano / vim etc) and add a new line at the bottom of the file, with your command:
modprobe -a ide-scsi
Hopefully you should now find your drivers are loaded at startup.
For the error when you boot, you'll need to edit your fstab file. This file tells Linux which drives to mount at startup. Its at /etc/fstab. Again, edit it as root in your favourite text editor. You can probably just comment out the line that refers to /dev/hdd, but I'm not an expert so do some research before you do that!