Machine_UDP_v5.ino Problem NEED HELP

i am new to this and picking the project up where it was previously left by my dad, i am working on the section control as that is where he got stuck, however anytime i try to upload the code to the Arduino clone i keep getting a compilation error code for line 18

The folder is unzipped and this file is in this folder?


yes everything is unzipped and in the same file

When you open the file it should open with different tabs for all the different files.