Interface Event Not Firing

I have an object linetrace to detect my other actors and fire the Player Use function event but It does not seem to want to fire. Also the target variable is a pale yellow colour for some reason.

http://i.imgur.com/6Quo44v.png

Ok I took another look at it and tried dragging off of the hit actor instead and it gave me this message one which appears to work.

I don’t know why though, It would be nice if someone explained. I cant seem to find anything out there that’s just clear and to the point.

http://i.imgur.com/aaAOXAA.png

Interface events are only triggered by interface “Messages”. You may have a function called “Player Use” which you were calling instead by accident. You can tell it is an interface message by the little envelop in the corner.