What I did was to further edit the newuser_signup.tmpl file and add asteriks after each field that is required. Above all the options, I put (is Spanish): * Required Fields
That warning, as well as every asterik is red. That's helped make this work out for me. Look here:
http://www.laondalatina.com/foros/newuser.php I don't know off hand whether this works w/ 6.4 or not. The avatar pop-up I have was backported from 6.4 by Josh for me and it's not in this mod. When I get around to upgrading my site to 6.4, I'll commission Josh to upgrade this mod also