Authorization for Serial Pring Enabler

[chris lynch]

I am working at getting my newer Mac OS 10.4 to print using my old Deskwriter 560c printer.  But this time around, I can't even get past the authorization page requirement when I click on  ( http://127.0.0.1:631/admin/?op=add-printer ).
The page morphs into this request for authorization from CUPS, asking my user name and password, if I am not mistaken.  That's all I
can think to put in the boxes, and what I put my user name and password in, it does not get me access.

Am I missing something?  I never saw this request from CUPS before when I accessed that Serial Print Enabler page a few months back.  Any ideas as to what to put in the authorization blanks?  Thanks.  Chris Lynch