I have had the Arduino Toolkit in my mind for a while now, and 2 days ago, I decided to give it a try (it looked really exciting to me). So I set to work, doing everything step by step, with an Arduino nano, and MCreator 1.7.9. The video did not work, so I went to the MCreator post (https://mcreator.net/wiki/mcreator-arduino), followed it step by step, with no solutions being brought up. I started to see if others had had these issues, and found a few solutions. I turned off my Firewall, tested the Arduino's serial capability through the IDE's serial monitor, etc. I tried my own solution to run the .jar file on administrator mode, to no avail either. I even reverted my MCreator version to the version on the video to see if that would help me at all: it didn't.
I'm not sure what else there is I can do to solve this, so I have come to you guys. The workspace I last used to test this is exported below. I would highly appreciate some help!