I am not using any third party plugins.
Here is my .capx file....
I tested out the default Space Blaster game to see if I would encounter the problem with it, and I did encounter the problem.
I still haven't found an answer.
However, I think the problem arises when I try to use the touch feature along with the mouse to control the player sprite movement and the left-click button to fire.
I don't define a mouse object when I use touch, so I am using the mouse without it being defined, and I am clicking on the left-mouse button to fire without it being defined, too.
This is really a bad programming practice, and I don't know why I didn't think about this earlier.
I'm going to try to bypass this problem by only using the mouse to control the sprite, but not use it also for firing bullet sprites, and I'm going to explicitly define a mouse object, too.
I really think this is the reason I am getting this error, but I will look into it further today when I return from school.
There might be a problem with the touch automatically detecting mouse activity or something.
Thank you for responding to me.