The URL to request a password reset is:
http://www.giantitp.com/forums/admincp/user.php?do=emailpassword
or
http://alt.giantitp.com/forums/admincp/user.php?do=emailpassword

You should be able to use the latter if the first one (www) doesn't work. I have already asked it to send you an email with your password reset code. Note that the link in the email will be to the www page and if the problem is persisting, you may need to change the url in the email from www to alt.