I followed the course a bit more and made it to Section 2 Lesson 16 and got both these same problems there as well, but I first encountered them on this lecture.
When opening the script to edit it, Visual Studio opens up initially. After I close the login window for VS and cancel the start up, Monodevelop opens up (this could be just Monodevelop opening as normal and it was simply loading while I was closing VS.)
Once Monodevelop opens up, I get this error:
Could not load project ‘NumberWizard.csproj’ with unknown item type ‘{E097FAD1-6243-4DAD-9C02-E9B9EFC3FFC1}’
However, after clicking OK, it seems to open up fine.
That is the folder I had looked in, but the Temp folder was not there while Unity was closed, however it did appear when I opened Unity and once I closed Unity, it disappeared again. I deleted the other files as you said, reopened Unity and tried opening the C# file again and ran into the exact same problem.