i checked syntanx and everything. i try to edit anytihng it give error

Hello, I'm integerating a new payment module in website script. but when I try edit any files in cgi folder (index.cgi) it's giving me error. not only that but even I am undoing my changes it's not working when I got 500 error I have to upload files from backup. I make following changes: index.cgi: ...