I think from what I understand keyboard are trigger events so ELSE does not work with it. Which is stated in the Manual
[quote:263r4iks]
Else
Run if the previous event did not run. Note that this condition does not pick any objects: if it follows an event that picks objects, in the Else event all instances revert to picked again. Else can only follow normal (non-triggered) events. It can also follow another Else event with other conditions to make an "if - else if - else" chain.
what you can do is switch to say:
if Right Arrow is NOT Pressed AND Left Arrow is NOT Pressed set Gravity to 5 (which you right click the condition and say INVERT)
So have a condition for if its pressed and another for if it isn't
I am not at my personal computer it is more of a shot in the dark. But I think the top condition with the green makes it a trigger event.
EDIT::
Sorry was typing my response when you replied.