Never had a USB floppy drive, so now I'm just guessing:
Make sure drive is unplugged
In a terminal, as root, command "tail -f /var/log/messages"
Plug in the drive and look for messages, see if you can see what name it is issued (/dev/something).
In another terminal: "mount /dev/something /mnt/floppy", watch the drive for activity and look for errors. When it settles: "mount", look for a successful operation.
I tried that and got the following result:
root:# tail -f /var/log/messages
Jan 21 15:45:13 vector kernel: [ 4296.248738] sd 8:0:0:0: [sdc] Write Protect is off
Jan 21 15:45:13 vector kernel: [ 4296.249488] sd 8:0:0:0: [sdc] Write cache: disabled, read cache: enabled, doesn't support DPO or FUA
Jan 21 15:45:13 vector kernel: [ 4296.261376] sdc: sdc1
Jan 21 15:45:13 vector kernel: [ 4296.263981] sd 8:0:0:0: [sdc] Attached SCSI removable disk
Jan 21 15:46:42 vector kernel: [ 4385.798921] usb 1-5: USB disconnect, device number 6
Jan 21 16:13:55 vector -- MARK --
Jan 21 16:33:55 vector -- MARK --
Jan 21 16:53:55 vector -- MARK --
Jan 21 17:13:55 vector -- MARK --
Jan 21 17:33:55 vector -- MARK --
Jan 21 17:53:55 vector -- MARK --
Jan 21 17:55:51 vector kernel: [12134.457022] usb 4-1: new full speed USB device number 2 using uhci_hcd
Jan 21 17:55:51 vector kernel: [12134.652036] usb 4-1: New USB device found, idVendor=057b, idProduct=0000
Jan 21 17:55:51 vector kernel: [12134.652042] usb 4-1: New USB device strings: Mfr=1, Product=2, SerialNumber=0
Jan 21 17:55:51 vector kernel: [12134.652046] usb 4-1: Product: USB Floppy Drive
Jan 21 17:55:51 vector kernel: [12134.652049] usb 4-1: Manufacturer: Y-E DATA
Jan 21 17:55:51 vector kernel: [12134.660130] scsi9 : usb-storage 4-1:1.0
Jan 21 17:55:52 vector kernel: [12135.665066] scsi 9:0:0:0: Direct-Access Y-E DATA USB-FDU 7.03 PQ: 0 ANSI: 0 CCS
Jan 21 17:55:52 vector kernel: [12135.665290] sd 9:0:0:0: Attached scsi generic sg4 type 0
Jan 21 17:55:52 vector kernel: [12135.777052] sd 9:0:0:0: [sdc] Attached SCSI removable disk
and also:
root:# mount/dev/something /mnt/floppy
bash: mount/dev/something: No such file or directory
vector://home/madscientist
root:# mount
/dev/sda1 on / type ext2 (rw)
cgroup on /sys/fs/cgroup type cgroup (rw)
tmpfs on /dev/shm type tmpfs (rw)
usbfs on /proc/bus/usb type usbfs (rw,devmode=0666)
fusectl on /sys/fs/fuse/connections type fusectl (rw)
gvfs-fuse-daemon on /home/madscientist/.gvfs type fuse.gvfs-fuse-daemon (rw,nosuid,nodev,user=madscientist)
So what do I try next?