Ducks go quack and fish go blub and the seal goes ow ow ow... What does the fox say? - Ring-ding-ding-ding-dingeringeding!? Gering-ding-ding-ding-dingeringeding!?! Nope? You should try harder explaining what you want to do. Something that makes sense to you doesn't have to make sense to other people.
I made it on Autoit 3.3.8.1, the problem arises due to the errors in the APIConstants.au3 that you may not have rectified/updated.
I replaced the includes and it would work without APIConstants w/o any problem on the stable release. Check the code again in the stable release.
Maybe you can pass the PID as a command line parameter in your Run() call, or set the PID in a environment variable.
In your setup, you will have to get the command line parameter or environment variable, and kill the process using the PID.
It's just an idea, there is probably an easier way...