it's better to post error message instead of error code alone.

there may be several reasons for crash:

-empty pointer('my' entity is not set or created at the moment).
-type mismatch(shoot_vector has to be either var array

or VECTOR structure

in both cases when you want to pass a vector you don't have add .x after the variable's name unless it's an entity struct and you want to access it's coordinate.

so, if that doesn't help - post error message, and the code where you define shoot_vector