I'm not sure its about this but some days ago i noticed that two old games of mine on kongregate(jimmy poo and ten levels) freezed when I did any input showing a similar error.
I just re-exported the games with the latest c2 build and this solved the problem..
p.s.
you can see the difference here:
Jimmy poo on scirra arcade, old version, it freezes when you click any input:
http://www.scirra.com/arcade/action/2234/jimmy-poo
Jimmy poo on kongregate, re-exported version, works:
http://www.kongregate.com/games/rujo/jimmy-poo