I am using Gutsy (7.10) Live CD environment, and when I stick a USB
device into the system, it mounts on /media/ubuntu710.

After inserting the USB device into your system, issue the command
from a command line window (aka Terminal):
$ mount

What do you see? My usb is mounted as follows:
/dev/sde1 on /media/ubuntu710 type vfat
(rw,nosuid,nodev,shortname=mixed,uid=999,utf8,umask=077,usefree)
/dev/sde2 on /media/casper-rw type ext2 (rw,nosuid,nodev)

Try checking in /media subdirectory from a command line window (aka
Terminal), i.e. Applications>Accessories>Terminal to see what
subdirectories may have been created.

What do you see? Any subdirectories?

Then simply do as I did, either (substituting your subdirectory for
ubuntu710 under /media):
$ ls /media/ubuntu710
or
$ cd /media/ubuntu710
$ ls