BuddyPress.org

Hi people, First post here…
Working on two very similar sites (both multi-site and buddypress).
http://redebrasilis.net
http://razoncartografica.net
Well, if you try to login and you just click on the field “username” you’ll see what’s happening: razoncartografica.net works well, I mean, it allows you to enter text (your login name), as expected…
But, on the other hand, redebrasilis.net loginbar keeps redirecting you to the sing-up page from the very moment you put your cursor on…
Why does this happen????? How can I fix it?????
Thanks!