My X7 does that often so I just select a couple of times until it runs. I find if I try to open Xbmc too soon after I get to launcher screen especially if Google is updating apps while trying to open Xbmc I get kicked back to launcher screen. You could also try going into android settings, apps, Xbmc then clear cashe and as a last resort clear data which will result in Xbmc doing a first run boot.