You can create the form in Dreamweaver, but it won't work until you have a proper script linked to it. Creating the form simply makes a section with the variables needed for the script to work, but you still need to add the code.
You can look for an appropriate script at http://hotscripts.com (try the PHP section). You can restrict the file format choices by requiring the uploaded files to have an extension in a pre-approved list which the script can check for acceptance.