I had this same problem, and the above solution worked for me! Thank you, Galloper!
It really IS extremely frustrating though, because I had no clue what was going on, and it took me half
an hour to find this post.
I hope that the next update will address this. I'm very new to both this program, and coding in general,
and something like this just adds to the struggles that I'm already having.
Bugs will happen, but something major, like our projects failing to run, ought to be detected, and we ought
to get some information and help from the program, at that point.
Thanks again!