There are hundreds of issues with forms that a developer should know. Similarly there are hundreds of issues in giving a feature of uploading files on your website. And there are thousands of hackers and spammers out there waiting for your mistakes.
DO NOT USE SOMETHING ON YOUR SITE THAT YOU DO NOT UNDERSTAND EXACTLY. I will suggest you to study PHP tutorials, google and get thousands of, on forms and file uploading. Then write your own script rather than using a ready made script blindly.