！。
Hey! What are you doing blocking my way?
Literal
Hey! What way-blocking are-doing [emph-のよ].
通せんぼ (or 通せん坊) is a children's game / childhood expression for physically blocking someone's passage, arms spread wide. It's playful or scolding when applied to adults. やってんの is the casual spoken contraction of やっているの, the nominalizer の giving a confrontational question tone. The final よ adds forceful emphasis. Short, sharp, and scolding.