It sounds like you may have a problem with the hard drive itself. Perhaps try sysinfo to see if the harddrive is mounted, or use the A590 hdtoolbox to see if you can repartition the drive. You could also use one of the GVP scsi utilities but instead of gvpscsi.device use scsi.device
If the drive is has Fast file system on it (and you need to save the data) you could also attempt using Disksalv
http://aminet.net/package/disk/salv/DiskSalv
