System keeps on chugging even if you don't have main.py

I accidentally ran the installer builder when my script was called 'goo.py' rather than 'main.py'. It still produced an exe and an installer. I had to dig through the output to notice that it emitted an error log indicating I didn't have main.py. it'd probably be best to fail the whole process at that point so users don't waste time as I did looking at the produced output that will never work