I got your fix dude
apparently, Unetbootin isn't available thru Lenny repos
The work around is you go get the reg no-specific one here
http://unetbootin.sourceforge.net/
hit the download button for Linux, the one beside windows
its called "unetbootin-377"
Take that after downloading. open a terminal and become root
then copy it to /usr/bin
or call up your file manager as root
or whatever your filemanager is..
Now, you gotta make a menu entry
I need to know what desktop your using?
Gnome/KDE,etc
To test it or run it
again become root in terminal
and do
it should pop up