I cant see any usb drive in that file.
In my fstab file, I can see the following, which is my usb drive/dev/sdb1
/media/ILLUSION vfat
rw,nosuid,nodev,uhelper=udisks,uid=1000,gid=1000,shortname=mixed,dmask=0077,utf8\
=1,flush 0 0

Can you please post the output of
gksudo gedit ../../etc/mtab &
And make sure your usb is plugged into the computer