goodo -

You can't see award seats from the screen you were looking at. Go back to the UA home page. Click on Award Travel (left column). Log in at the next screen. Enter your proposed itinerary at the next screen.

What you will see, expanding on and responding to Empress' post, is award availability in the following classes:

R = XF = First Class
X = NF = First Class Upgrade from Business
O = XC = Business Class
I = NC = Business Class upgrade from Economy
N = XY = Economy Class
E = Economy Class (available only to 1K pax)