I downloaded your capx and played around with it for a while. It will work if you do the following:
For the main event:
If left arrow is down
AND
if down arrow / up arrow / right arrow are not down
Then set animation to walk left.
Then place the sub events exactly as you have them.
Do this for right/down and up as well. This will make it so the animations work correctly in all 8 directions.
You'll still need to add some instance variables or something for when you turn around to make the animations change properly.