Dennis, my sites are all upgraded from prior versions and do have that module. I'm sorry that I don't know how to advise you on adding an older module to your application.

I have a thought, but it is not pretty. You might try creating a new site with a lower version of DNN, upgrade it to 7.1 and add the old File Manager to the page. Then create a site template from your current site and apply it to your newly upgraded site. If you are desperate enough to try this, allow a chunk of time. Because you also need to reinstall all your purchased modules and skins and the export and import process for the site templates is error prone. I have often had to edit the template's xml file manually to get it to import. 

Before doing all that, I would attempt to figure out how to copy the module out of an old installation and paste it into your new one and wire it in. (If it is even possible.)

I created a new module from a control, using:

/DesktopModules/Admin/FileManager/filemanager.ascx

I'm not sure if files were already there or if I took them from an older version I had on my dev machine.

I'm just happy to have a work around.  I use the synchronize files feature a lot so it will recognize new files I've uploaded via FTP immediately.