I am trying to have the form include the attachment, but the attachment does not come through.

In PHP settings on your server is set  "upload_max_filesize" parameter (you can go to URL http://your.site.com/formmaker_folder/info.php and see it). Try to attach file with size lesser than it is set in upload_max_filesize and you will see that it will be delivered. Please ask your ISP to increase upload_max_filesize parameter.
After that you need to insert following hidden field in HTML code of your form after <form> tag

where N - is maximum file size in Kilobytes (it have to be lesser than upload_max_filesize).

User upload file on the server. Server attaches this file to email and deletes it. So no files are hold on the server.