There's an incorrect result listed for Roger Federer: he didn't lose to Steve Johnson on Tue Jun 10, 2014, at Halle (Gary Weber). In fact, they didn't even play each other. Steve Johnson's 6-4 6-2 victory was against Albano Olivetti. Here's the official draw/results:
http://www.atpworldtour.com/share/event-draws.aspx?year=2014&eventid=500&draw=ms
So to fix it, you should reassign Steve Johnson's opponent from Federer to Olivetti.