That code looks like it's going to restart the animation every tick -- so it's essentially stuck playing the first frame of the animation over and over again.
You might try removing the condition
and replacing it with an inverted animation check
- X is playing animation "Walking"
which you can do by creating an "is animation playing" condition, right-clicking on it, and selecting "invert".
In short, this new code would only play the animation if it wasn't already playing.