PHP Contact Form Mail Help

I am using this form <[login to view URL]> at <[login to view URL]>. I copied the files exactly but the file is too big error does not work. It works on the sample page <[login to view URL]> but not on my server. If I try to upload a file larger than 2 MB, I should receive the error: The file is too big. File size should be less than 2024 KB Instead of the error appearing, the email sends, but the files that were too big are not attached to the email. I just need to make the error appear. There is another small issues as well: the sender comes from <nobody@[login to view URL]> instead of the actual email address of the sender.