I have seen this topic for other products, but not for ADAudit.  

Running the command prompt as admin logged into the server with the service account that has the access to the MS SQL Server database.

After putting in the host name into the ADAudit Plus - DB Configuration application, I get a "Socket Time out while fetching the database instances from host", error. If I ignore this and test the connection with the database name filled out, the command prompt in the background displays a javascript error:  "Exception in thread "AWT-EventQueue-0" java.lang.NullPointerException", with a big dump after it. 

I have tried restarting the SQL browser service, and checked the firewall settings.  I am able to open up a telnet session with the MS SQL server on port 1433 with no issue.