That seems to be the opposite to what you said in the first post - "US Airways return flights all appear to be a problem with United award reservations".

To ask my question in a different way - you're trying to book a certain combination of flights, and they aren't showing up when you do a search. Generally if they don't show up it's because there is no award availability for those flights. What's leading you to believe that there is award availability, and something is wrong?