trouble with first cloud formation script

[rgindallas]

I'm having trouble getting the first cloud formation script to fully execute....It will run for several minutes and even start creating instances, but ultimately it rolls back the entire stack. Do you have any ideas for common errors or omissions? I included the screen shot with the error i'm getting and a zip file with the deploy and yaml files. I'm trying this on a windows system using git bash.
***when i tried to copied the code as-is from the lesson console and tried to run it, i was getting an error about the parameter override argument so i tried to tweak it based on similar question/answers in stack overflow. I don't know if I have it correct now, but my current problem doesn't seem related to that. Is this a common thing or do I have to tweak something in my bash setup?
thanks and I'm really learning a lot already. I'm studying for the csaa cert and this has helped to cement a lot of concepts.
Thanks.
main2.zip