This error, "You must have at least one upload form on the page to use File Upload" displays when applying the Upload File Server behavior.
This error occurs because the form tags encoding type is not set to multipart/form-data. On the tag selector, select the Form tag on your page, then in the Property Inspector, select multipart/form-data from the Enctype menu.

Digital File Pro adds server side code to your page. Before you can add Digital File Pro, you will need to:

1. Define a dynamic site in Dreamweaver (To define a dynamic site, choose Site > Define site, and select a supported server model from the Testing Server category).

2. Create a new page using your selected server model and save it to the site you have defined.

When you apply the File Upload server behavior to your page, there is a new binding group added to the bindings panel called "WA Upload Files Global Status". This contains a Debug Info Binding that can be added to your page to provide information about the status of an upload.

For PHP users, by default PHP is configured to allow a maximum file upload of 2MB, this can be increased by editing the php.ini file.

In the php.ini file, locate the following line: upload_max_filesize = 2M. Change this setting to accommodate for the file size you wish to be able to upload. There are a few other settings in the php.ini file that can affect the maximum file upload size (file_uploads, upload_max_filesize, max_input_time, memory_limit, max_execution_time, post_max_size) The following webpage has more information on each of these settings:

http://www.php.net/manual/en/ini.list.php