Drive backup to D-Link NAS-323 only via right click on local drive letter

Hello,

Unfortunately I was not able to find a solution for the following Issue: Whenever I try to start a Backup of local drives of my computer to my D-Link DNS-323 NAS using the "normal" program entrance, ATH2012 prompts for my Windows accounts username and password. Whatever I insert as username (Username, PC-Name\Username, PC-Name/Username and others), it keeps prompting for the credentials. I am not able to start the backup. I am running Windows 7 Home Premium.

When I instead use the Windows Explorers's context menu and click right to a local drive, I get into the same user interface page as describe above, however, ATH2012 promps only once for username and password. After having inserted the latter, the backup starts and runs without further issues.

Can anybody helpme to get the "normal" program entrance to work?

Regards,
Bumi