Error, not compiling

Have been encountering this problem for a while now, the project refuses to compile.
I have tried it on two different computers, and it is a different error?
Can someone please tell me what the error seems to be?

I have tried it on other macs ( this is in the computer labs, so there are many macs). It works on some, and then refuses to compile the same project.

Am I missing files?
( These two images are from two different macs, its the same project. Also the project does compile, but on the third mac )
Image 1

Image 2

Thank you! :slight_smile: