Login Error 016-781 with Dell MFP 3115cn ptr & WIN Server 2008 R2

I have a very annoying issue trying to setup a Dell MFP 3115cn printer to scan to a shared folder on a Windows Server 2008 R2.  I've carfully read all the Dell manuals on how to setup a scanned folder on the server and all the parameters on the web interface on the printer.  No matter what combination I select it shows a login error 016-781 on the printer console.

I've already setup a shared folder on the server with all rights to Everyone group + a select few users on the LAN.  I CANNOT enable Network Discovery even though I'm logged is a the Administrator (Group Policy or Registry fix needed here?).  

I've also tried using SMB and FTP for the Servery Type on the printer setup but both fail.  Could a specific port need to be allowed in the Server firewall?  I've also tried turning OFF the server firewall but the logon to the server from the printer still fails.

I can PING the printer IP address OK from the server.

WHAT AM I MISSING HERE?  Can someone please help me solve this puzzle?

Thanks,
Shane D.

P.S. - Is it OK to leave an email address or phone number here for contacting me?  I haven't used this site in a while but I've been a member for over 2 yrs.