Comment 2 for bug 649716

From http://www.thinkwiki.org/wiki/How_to_enable_the_fingerprint_reader_with_ThinkFinger :
"You should see the "Password or swipe finger:" prompt when trying to sudo or su. If you don't, you probably do not have the "User level driver support" compiled into your kernel or the "uinput" module loaded!"

For some reason driver isn't loading:
sudo modprobe uinput
lsmod | grep uinput

Is it compiled in?