other.id wont work, you need to call your collisions in the step event, using something like:
other = collision_rectangle(x1,y1,x2,y2,true,true)
that sets the variable other to the id of the object that is collided with. the x's and y's are self explanatory, the first true is wether or not to use precise collisions, the second is to check and make sure the collided instance is not the instance calling the code.
from there you can use checks to make sure it is the right object, etc.