Have you ever accessed this drive from Linux ? It could have a NTFS file system and you don't have NTFS support installed.. I would suggest installing ntfs-3g
and using that to try and mount the drive. ntfs-3g is included in the repositories for most distros.
With the drive plugged in, open a terminal and type fdisk -l
that should show all the drives connected to your system and what their file systems are. You should be able to tell if my guess about NTFS is correct or not..