Hello!

Looks like you have problem with database. As far as I understand you have installed UNA again, but during installation UNA cleans database, thus you have no any records now.

When you migrate the all data with files and database you don't need to install it again. Just upload files to new site's root folder and then upload database to the new server. 

After that correct in inc/header.inc.php file the next:

1) credentials for database

2) paths to the root of the server

3) site's url 

and clean the cache and cache_public folders. 

Now you old site should work fine.