I found a partial solution. If in the file /var/www/fog/lib/reg-task/registration-class.php on the line where $userTest is, I change the values of $username and $password to the real values through which I log in to the FOG server, I get quickreg including deploy image… This is not a system solution and should be fixed by the developer. (Again, this is for version 1.6, on 1.5.10 this works correctly).
M