usb flash drives

[JD]

Before I sign up for psychiatric treatment, can someone tell me what (if
anything) I'm doing wrong here?

Machine 1:
Plug in flash drive
dmesg (as sudo)

see that /dev/sde , /dev/sde1 are there

mkdir /mnt/usb

mount /dev/sde1 /mnt/usb

check this dir, it's ok

cp <somefile> /mnt/usb

ls /mnt/usb
<somefile> 

umount /mnt/usb

Machine 2:

Plug in flash drive

Konqueror dialog opens
I open a conqueror window...
0 items, 0 folders

In a term on machine 2
dmesg (as sudo)

see that /dev/sdb , /dev/sdb1 are there

mkdir /mnt/usb

mount /dev/sdb1 /mnt/usb

check this dir, it's ok

ls -l /mnt/usb

(empty)

Why?