LinuxQuestions.org - Unable to mount the volume 'WD Passport'

I upgraded to Ubuntu 7.10. The WD Passport external portable hard disk was mountable and acessible at that time and appeared on my desktop whenever I plugged it into a usb port on my laptop.

Then something happened such that now when I plug it in, I get the following message:

Cannot mount volume.
Unable to mount the volume 'WD Passport'.

mount:wrong fs type,bad option,bad superblock on /dev/sda1,
missing codepage or helper program, or other error
In some cases useful info is found in syslog - try dmesg | tail or so

So I issue the following commands as suggested:
/> dmesg
FAT: Unrecognized mount option "usefree" or missing value

Then I open the Device Manager entry for WD Passport. It reads as follows:
volume.mount.valid.options
strlist "ro","sync",...,"usefree"

Then I issue the following commands:
/> pg /etc/mtab
/> umount -l /dev/sda1
umount: /dev/sda1: not mounted

By the way...
/> uname -r
2.6.20-16-generic

What to do? What to do? I don't know how to remove the "usefree" option if that's what it takes.

Thanks in advance