I have Mac OS X 10.5.1, and I am trying to mount an external hard drive that was written onto using a linux box.  Now that I have installed ExtFSDiskManager, when I double click on the executable, nothing seems to happen.  However, before, when I plugged in the drive, finder would say it is not readable.  Now, I don't see much of anything.  I do see that there are two new "disks" in the /dev directory
disk3 and disk3s1 when I plug in the drive.  When I try to mount them, I get no success.
:/] gavin% sudo mount_ext2 -o ro /dev/disk3s1 mnt
mount_ext2: /mnt: No such file or directory

I am asking for some explanation of what I have done, and also how to mount the drive.  Will it mount in the /Volumes directory?