The animations either don't exist, are numbered wrong, or have the wrong sprites. Additionally, it could also have something to do with the hitdef, though I'm not sure.Also this should be under help, not in projects.
Usually, P1 hits P2 and, P2 is sent to a custom statedef. P2's custom state uses P1's *.air file to display the animation. If P1's statedef doesn't tell P2 to change animations, it wont. Everything 087-B mentioned might be true also.