Taking an intro to programming/VB.NET class and my professor can’t open my sample program

Question

Followed all the steps to make a basic calculator program using VB.NET Compressed the file and submitted it but my professor gets an error message when trying to open it. She has no idea why and says I must of done something wrong but when I run my code everything works fine. trying to find a solution online but there's no clear solution.

this is what my professor sees when she opens my file